you can either get the M3 or R4. Exactly the same thing. It looks just like a regular DS cartridge but you can put a microSD card in there. Right now, they cant play GBA games, but it can do music, movies, ebooks, nes, snes, and of course ds games. all you need to get started is the m3 or r4 and a microsd. you shouldnt pay more than $40 for it and microsd's are cheap.