I worked for GameStop to close a work gap before I started teaching. They make all their profit from used games. Exactly what was mentioned above, buy for $18, sell for $150. As a worker you are told to push the used stuff, both games and systems. They computer will make you override on a new game if a used is in stock.
The other things they push hard are the memberships which is basically free money. You have to spend a huge amount of money there to break even on it. Also reservations on new games is basically just a lay-a-away program.
They have zero vision. Swore up and down what happened to Toys-R-Us would not & could not happen to them. Days are numbered for them; between the Fortnight model of free games and downloading games direct they have turned to used stuff to get by.
It wont last but what a GREAT going out of business sale they will have!