The only thing free users can't do that vip or above can is
1. Use mirror mode.
2. Run unlimited clients. (Free users are stuck with 1 client and 2 tabs)
3. No ads on website and client (Free users get ads)
There's a few other forum additions you get like signature space increased; Similar shit like that.
EDIT: Try looting, it's fairly low on bans and easy to start botting.