https://www.gamespot.com/articles/get-more-cash-from-us-gamestop-trade-ins-for-a-lim/1100-6458137/

If you have a pile of games you're ready to trade in, you can get extra cash at GameStop for a limited time. Usually when you trade in a game, you can choose to have it paid out as a lower amount of cash or a higher amount of store credit. From now through April 22, however, GameStop is paying out just as much cash as it would store credit.

There are a couple details to note here. It's only valid at participating stores in the US and Guam, and it's not valid in California (sorry, folks). You can see a list of the ineligible stores here.