Nothing is more frustrating than buying a new pair of headphones, an OLED TV, or a backpack just to find out that you could have gotten it for a lot cheaper somewhere else. In order to keep customers happy — and prevent them from going elsewhere — many retailers offer price-matching policies where they promise to match a lower price you’ve found elsewhere. That’s information that could come in handy given Amazon’s second Prime Day event this year — aka Prime Big Deal Days — will take place on October 10th and 11th.

What follows are the price-matching policies for a variety of major retailers. There are a few things to make note of here. First, all price-matching policies have a number of rules attached to them. We’ve summarized some of the rules here, but you’d be advised to go to the links that we’ve provided and read the policy carefully. Second, and logically enough, retailers that serve as marketplaces for other sellers, such as Costco, don’t have price-matching policies.

Lastly, there are always exceptions to the rules. If you’re looking for a deal on a product and you know it’s available for a lower price elsewhere (or it was previously offered at the same retailer), it never hurts to call or chat with a customer service rep and ask if they’ll match the price. After all, what do you have to lose?

Amazon doesn’t offer price matching. Full stop. You can contact customer support, but even if you’re an Amazon Prime customer, they’re not likely going to help you out.

That said, Amazon does offer a pretty liberal return policy, meaning you can often return an item you purchased from Amazon if it’s available for less elsewhere (or at Amazon). Then, you can just repurchase the product wherever it’s cheapest.

Target will match the price of an item that you find for less either at Target or at a select list of competitors if you ask for it at the time of or within 14 days of your purchase. You must bring the original ad or listing, whether digital or in print, along with your receipt into the store. Alternatively, you can call for online purchases at 1-800-591-3869 or chat online via contactus.target.com.

Be mindful, however, that this price-matching policy does not apply to doorbusters and competitors’ lightning sales, like those that Amazon offers. It also doesn’t apply to products that require that you log in to see the price, “Marketplace” items from third-party sellers, or lower-priced items purchased from other Target stores.

Best Buy’s Price Match Guarantee states that a product could be eligible for a price reduction if it’s new, identical to the competitor’s product, immediately available at a qualifying competitor’s store or on its site, and not shown on Best Buy’s exclusion list (which includes “items for sale the Friday before Thanksgiving Day through the Monday after Thanksgiving”).

To get the difference, you have to contact Best Buy via its on-site chat and be able to show the ad or website with a lower price point. Alternatively, you can call 1-888-237-8289 or visit any Best Buy or Pacific Sales store.

Best Buy will also, upon request, match an in-store or online price that was lowered during the return and exchange period, which typically lasts up to 15 days.

Walmart doesn’t price-match the prices of its competitors. However, Walmart’s online store offers price matching on items purchased from Walmart stores if the item is in stock at Walmart.com. However, the policy doesn’t apply to those who live in Alaska, Hawaii, or Puerto Rico. Additionally, it doesn’t apply to special event prices, like those seen during Black Friday. Walmart also does not retroactively price-match items bought from Walmart.com that have dropped in price after the time of purchase. The retailer also doesn’t price-match items purchased from Walmart Marketplace retailers or third-party sellers.

While we’ve seen some claims that Apple will price-match up to 10 percent for products bought at certain major retailers, there is no official policy on the company’s website.

Apple does say that if it reduces its price on an Apple-branded product within 14 days from when you received your item, you can visit an Apple Store or contact the Apple Contact Center at 1-800-676-2775 to request a refund or get credit for the price difference. However, that doesn’t apply to special sales like Black Friday or Cyber Monday.

B&H says that it might be able to honor a current lower price or match the price of a competitor, but it does so on a case-by-case basis. You have to contact its Customer Service team using the on-site chat, email, or by calling 800-606-6969 / 212-444-6615.

Costco does not price-match with competitors. However, according to the website, it will issue a credit for the difference between the price a member has paid and a promotional price if you bought the item online at Costco and requested the credit up to 30 days before the change in price. If you bought the product from a Costco warehouse location, visit the membership counter at the store where you made the purchase. Costco doesn’t price-match items bought from Costco warehouses with Costco.com purchases.

Dell will price-match identical products from Dell, Amazon, Best Buy, Walmart, Target, HP, Apple, Lenovo, and a number of other retailers. You can call 1-877-275-3355 or chat online to run a price check, but you’ll need to provide a link to the competitor’s product.

You can also contact the company about a price difference within 30 days of purchase. However, there is a long list of restrictions, and none of this is available between Thanksgiving Day and the Monday following Thanksgiving (or on Green Monday).

If you find a lower price from a qualifying competitor on an eBay Deal item that you bought within 48 hours — or on another product with the “Best Price Guarantee” symbol attached to it — you’ll get “110 percent” of the difference. That means eBay will give you an eBay coupon for the difference in price between what you bought the item for and what the competitor is selling it for, plus an additional 10 percent of that price difference. Note, however, that these coupons will expire within 30 days of being issued.

The products must be new and unopened and identical to the competitor’s item. You have to contact eBay Customer Service, and if they verify your claims are legitimate, you will receive the coupon and be able to use it toward your next eBay purchase.

GameStop does not mention an official price-matching policy on its website. Last year, however, GameStop tweeted that the store will price-match items sold and shipped by Amazon as long as they’re available online or in-store. Although GameStop only mentioned Amazon in the tweet, others have reported that the store will price-match items purchased from Target and elsewhere.

Google will match online pricing from select retailers — specifically Amazon, Best Buy, Walmart, B&H Photo, and Target — if a request is made within the standard return period. It doesn’t, however, match preorder pricing from other retailers or carrier deals. The product also must be identical, right down to the color and configuration, and must be in stock. Plus, you need to provide a public link to the promo page or product listing to verify the rival’s price.

You may also get the difference if a product purchased from the Google Store lowers in price within the standard return period. To get the price match or correction, contact Google.

The Home Depot will match the price of identical, in-stock products from other retailers, except for membership-based wholesalers. The price-match policy does not apply to special events like Black Friday, though, and you must bring the ad or listing with you in-store to the register. Additionally, The Home Depot will only honor requests submitted by the original buyer — no friends or family allowed.

According to HP’s website, the company will match the current pretax price for new comparable PCs and identical HP printer, display, and accessory model numbers from nationally recognized online retailers, such as Dell, Amazon, Newegg, and Best Buy. The specs have to be the same, but the product model number does not need to be identical for computers. You have to ask for the match at the time of purchase by calling 1-800-888-0229. You can’t request a price match via email or chat, though, and the policy does not extend to items bought during promotional periods. It also doesn’t apply to membership stores like Costco and Sam’s Club.

If you find a comparable product at a lower price during the return period, you can email HP at [email protected]. This only applies to branded HP products and doesn’t apply to products purchased during certain promotional events. This includes Green Monday and products on sale during the week of Thanksgiving and the week after.

Lenovo matches pricing on comparable PCs from Lenovo, HP, or Dell with the same key specs as long as they’re sold through a list of recognized retailers. The comparable PC also must be in stock and readily available from both Lenovo and the competing retailer, and you have to contact a Lenovo sales rep in order to facilitate the match.

That said, you can’t take advantage of coupons or special discounts while receiving a price match, and the policy doesn’t apply to membership stores like Costco. The policy also doesn’t apply to “Marketplace” items where third parties fulfill the order, so double-check that you bought the product directly from the retailer.

Lenovo also offers a price guarantee refund for laptops and personal desktop computers bought from Lenovo.com within 30 days of purchase. To receive a refund, you must contact Customer Care and show the lower price of the identical product offered on Lenovo.com. This policy doesn’t apply to doorbuster or clearance products, however.

Lowe’s will match the price of identical, in-stock products when you present an ad, product listing, or photo from a qualifying online or local retailer, including Amazon, Best Buy, Target, and Walmart. The product must be purchased directly from the retailer and not a third-party seller, and it doesn’t apply to special sales like Black Friday. Lowe’s also doesn’t match prices from one Lowe’s store to another. To request a price match, head to the store, call 1-877-465-6937, or chat online.

Microsoft will refund you the difference if it lowers the price of a physical product purchased online from the Microsoft Store within 60 days of purchase. You can contact Microsoft’s Sales and Support team at 1-877-696-7786 to get a refund. If you purchase an item from a Microsoft Experience Center, you’ll have to go back to that location with your receipt.

Newegg offers price matching on select items; these products are identified by the label “Price Match Guarantee” that appears in the price box on the right side of the product page. This applies whether you find that lower price on Newegg or at what Newegg judges to be a major retailer. Regardless, you need to notify Newegg of the lower price within 14 days of purchase. You’ll then be issued a credit you can use on the Newegg website, though you’ll only have 90 days to do so.

Newegg’s price-match guarantee is not valid during major holiday sales events, including Black Friday, Cyber Monday, and Green Monday.

You can request a price match against other Sam’s Club stores but not competitors. Note that this doesn’t apply to items on markdown or clearance.