They're not available on the 3DS yet, and the 10 GBA games announced apparently won't be on the shop at all. We don't know. --- http://www.ps3trophies.com/card/9/Shift_Breaker.png http://dlcquickplay.com/user/shift_breaker - My RB3/GH:WoR songs.
There has been no price set, and from what people are saying, the gba games will not be sold and will be strictly for the ambassador program.
As for NES games, they're adding features such as multiplayer, I would assume they would charge more than $5 which is how much they are on the wii shop. --- "Yo bronx, stop being a turbo nerd and go outside." -FAT____MAN
I"d say an approximate value for the GBA games would be $8; many GBA games I've played are comparable to SNES games, and SNES games sell for that price, though honestly, I could see Nintendo charging more for them on the basis that they're newer. --- If you're a human and not feeling creative, make this your signature.