From EB's site: will almost get you a GBA SP, crappy deal if you ask me, but it's the only one I know of now.
GBA system & 5 GBA games - $50 trade-in credit Active: Now - 7/30/2005
Trade-in a working PO-GBA SYSTEM ALL and 5 pre-played GBA games and receive $50.00 trade-in credit. No titles excluded from trade. May not be combined with any other offer or discount. While supplies last. Typographical errors are not the responsibility of EB Games. See sales associate for complete details. Limit one per customer. Boxes and Instructions are NOT required.