It always amazes me that there is very little interest on Slickdeals in Gamestop's used game promotions. Some are pretty good. This 4 for $40 deal is pretty bad--many of the games are less than $10 already. But there are 392 games on the list and many of these Xbox 360 and PS3 games are selling used in the $14.99 - 19.99 range, so there is potential if you get lucky to find a store that has 4 games in that price range that you are interested in.
Thankfully, CheapAssGamer user blackbeard4886 created a Google docs spreadsheet that lists not only the current used prices but also trade in values etc. if you want to try to flip the games.
For Reference: http://www.gamestop.com/collectio...-variant-1
See post with link to Google document: https://www.cheapassgamer.com/top...p=13413700
If you purchase something through a post on our site, Slickdeals may get a small share of the sale.