[MaisterK]

How much bandwidth need a standar VPS running a samp server with aprox 70-100 players and smf forum?

3TB is enough?

[iKarim]

Depends on your forum traffic but 3TB is mostly enough.

[Mark_Weston]

More than enough, SA-MP doesn't eat up much at all. The forum won't each much of your traffic either if you keep images hosted somewhere else aka not on your server.