GameStop.com has Buy 2 Get 2 Free on Pre-Owned Games priced $9.99 or less (look for marked items). Shipping is $6, otherwise shipping is free on $35.
Note, Add 4 qualifying games to cart (2 least expensive games will be free). Availability for store pickup varies by location
Note, Add 4 qualifying games to cart (2 least expensive games will be free). Availability for store pickup varies by location