does the 3ds have a shop channel where you can buy and download gameboy advanced games?

need to know before buying a 3ds AND a ds lite.

Last time I checked, yes.

Don't buy one. I haven't used mine in like 20 months tbh.

I don't think they sell any GBA games, no. Only GB and GBC.

Yes it does (or will). Not sure if it's the SNES one already available but both will

It has the E shop but it sucks

cause i want to get back into some games i use to play and plus i want to play new 3ds games..

i want to play the old metroid GBA games.

also can you play regular DS games on the 3DS?

No, only GB/GBC/NES games. Yes, you can.

You can play DS games on the 3DS and some GBA games are sold as a Virtual Console in the E-Shop. It doesn't feature all the GBA games though.

I'd recommend you to get a 3DS XL, it's better in every way than the original 3DS.
Also, you could better buy a GBA SP instead of a DS Lite to play GBA games on, since the 3DS can play DS games too.