So I am looking into playing Pokemon again with my sister. I played Red and Blue when they first hit the US and then Yellow a year later. After that my GBC was stolen and my GBA was boring.

I was wondering what Gameboy I should get. GBA SP 101 for the brighter screen or something else? I want to play the originals again and work my way up from there. Also is 3bay still the best spot to find a GBA SP?

Just use a GBA phone emulator if that's all you want to do...The full version of the MyBoy GBA emulator ($4.99) allows trading/battling over a WIFI connection and you can play through the games with fast forward.