Trading in an old iPhone is becoming easier than ever. You simply need to have an iPhone in good working condition, bring it to a nearby retailer, carrier store, or even Apple’s stores, and get some cash back. Often, those iPhones are resold to shoppers looking for deals on nice, older handsets.

But choosing the wrong place to turn in an iPhone could leave money on the table. So, the folks over at Flipsy recently released a 2018 report on iPhone selling options. And their findings should go a long way in helping you to maximize your value.

First off, you need to keep in mind that some places will pay you cash for your old iPhones and others will give you credit to put toward a new handset. In most cases, carriers will give the credit, and other locations, like kiosks, online marketplaces, and online buyback stores, will give you cash.

In its study, Flipsy examined kiosks, carriers, online marketplaces, and online buyback stores. It evaluated values on base iPhone models. It didn’t break out the data by individual carrier or store, however, so your mileage may vary.

However, online marketplaces appear to be the best places to get value on your old iPhone. The iPhone X, for instance, fetches $643 in cash at those locations, compared to $587 at buyback stores and $340 at kiosks. You’ll get $565 from carriers, but that’s in a credit.

It’s a similar story for the iPhone 8, which will yield $459 in cash at online marketplaces. If you go with an online buyback store, you can expect $419 in cash, and kiosks will give you $200. Carriers will offer a credit of $340. Values at online marketplaces for the iPhone 7 and iPhone 6s tally $270 and $170, respectively.

Many online services give you the ability to see what values companies are assigning to old iPhones. So, before you head out, be sure to check out those prices to see where in each category you’ll get the most value.