VBA is the best and most popular Gameboy Advance emulator around. Emulates GBA, GBC, SGB, GBA roms! Supports ZIP-ed roms, so that after downloading files from the net you don't even have to un-zip them
I went to auction at a mom/pops video game store few months ago that was closing, and bought 11 slims for $200, 1 was DOA but 10 work fine. so hella deal. Already rgh3'ed 8 of them. But most younger kids don't even want anymore, unless it plays stupid "fortnight", or newer shit.