GTA:SA has no online by default, and the multiplayer mod isn't compatible with the Steam version I'm pretty sure.
Aren't MTA and samp add-ons to the original games?
Is the Non-steam version non-cd? :o
Like, No-CD? No. It has to be a CD if you buy it retail, but if you buy it on Impulse or Direct2Drive then it's no-cd.
You can get a No-CD crack. It's legal if you legally own the game, of course.
How much does it cost nowadays in stores? (nonsteam)
I wanted to mod it for the online mode.Anyway, what version should I buy? (Steam or not steam)
You can downgrade steam version very easily to mod it,That's what I did, and I can enjoy SA:MP on steam.Also, The steam version works on Windows 7. I don't know about the other versions, but you could easily install a windows 7 crack if you do not buy it from a store.