I like to go to Gamestop sometimes after work and browse around. They have a small-medium sized…read morecollection of games for the Nintendo DS, but what they lack in quantity they make up in quality - there are a lot of Games at Gamestop that are harder to find elsewhere and aren't stocked on routine basis by larger stores.
You can buy and sell used games here, but it's not a particularly fair deal. A used game will cost you only a few euros under the price of a new game, and selling a used game will get you 6eu discount on a purchase. Depending on which used game it is you're looking to buy or sell, you'll probably make a better deal on Ebay or even at a flea market.
I don't at all like the fact that they unpack all the games and store the game cartridges in drawers. This removes the joy of unpacking a new game and knowing you're the first to handle it without a package. This is, in some cases, a good enough reason for me to shop elsewhere.
To Gamestop's defense, they also buy and sell used accessories at a decent price, so if you're looking for a game cable, charger or controller, you'll find these here for cheap.
I recommend Gamestop if you're looking for a specific, hard-to find game or games for an end-of-life platform, like the GBA or Gamecube. It's located on the basement floor of the Europa Passage, so it's easy to get to with all major lines of transportation in the city.
