Wireless Authentication/Bandwidth limiting/router

[amazo2]

What is the least expensive solution for authenticating wireless users on a network. I need to limit their bandwidth and make sure they are who they say they are and route to the internet. I am aware of NoCat Auth (I am not a Linux user) and Reefedge's Dolphin (limited to 5 users).

I need the ability to have at least 25 users authenticated. I have tried to configure Mikrotik's router software but can't make it configure. The manual is rather obtuse.

Any ideas?

Thanks,

Kim