Hi,
Thanks for your question! To be honest it was not what I intended. What I wanted was that everyone could connect from anywhere. This is possible of course, but it has a significant consequence that everyone that obtains the credentials could connect with unlimited devices. This is not the intention. Then I had heard about a radius server; a radius servers takes care of the authentication. I found out that a radius server could do simulatenous use checking. So I started working on that and had the authentication working at some point, but I didn't achieve to let simulatenous-use checking work. I enabled it, but it doesn't work because the vpn server doesn't send accounting packages so the radius server doesn't know if a user is connected or not. Unfortunately there is as far as I know right now, noway to achieve this...
Then I got the idea to limit the ipadresses an user can connect from.
I understand your concern, but most people forget is that another ipaddress doesn't make you anonymouse, if we talk about a vpn. What really makes you anonymouse or not is if the provider logs your traffic. If it don't, there is noway to make a link between your ipaddress and your traffic and thus nothing to give out. Except a connection log in our case, but that is useless without a traffic log. Even if I didn't ask for ipaddresses then the servers gets it anyway when you connect to our vpn server. Otherwise it is not possible to establish a connection.
About the price: I think it is reasonably priced, most providers have a price range between 2.5 and 5 dollars per month.
I hope I have answered your questions, but if you still have questions don't hesitate to ask them.

PS: I will send you a pm soon.
Mart