can i do that?

If you mean the roms that you download, first you have to buy a GBA backup device like the "Flash Advance Linker Set" which comes with 64, 128, or 256mb card, which lets you send roms so you can play them, i think you can also take the data off the carts so you can save the info on your PC. check this link out "http://interesting-devices.com/Products/nintendo/gameboy/" also search on google for GBA backup, theres loads of info.

thanks, but can u find some substitute product that is cheaper? because it cost more then my gba and 3 games

iv seen plans on building your own at http://www.hh.se/stud/d99tibr/ but if you think about the roms you can download from sites and morph, etc. Your going to get alot of games for your money. I think there are cheaper flashers around, but from what iv heard, some of the cheaper ones are less reliable. Try asking someone in the customers opinion about which is the best GBA flasher, hope this helps.

thanks, i will do some research on it and will ask around. one more thing, can i buy this in stores? like bestbuy or EB?