I am looking for a VPN server like OpenVPN that supports bandwidth caps for users. I posted an original question which in which I asked for a VPN server that supported bandwidth throttling - which is incorrect and I am sorry for this. What I am actually asking for is a VPN server that supports per-user bandwidth caps.
By finding Windows VPN server software that does this, I can provide a VPN service to my customers with a 1GB cap for free users. Users would be able to use the VPN up until their bandwidth cap, then it would cut off unless they upgraded their package.