I got the latest KB Toys email newsletter, and it advertises Buy 2 Get 1 Free on all games excluding hardware & bundles.
I know KB probably has tons of crap, however its worth mentioning.
EB/GS has now stopped selling new GBA games, and in fact has converted all their left over new stock of GBA to used (just like Cube a few weeks ago). You might be able to pick up some seeled GBA games at used prices.