Good Donation Addon

Ok so for my gmod Terrortown server, i want to set up a way for people to donate! What is a good in game donation thingy, that might ask if they want to donate on the motd or something good. I want it to look user friendly. Also i want it to maybe like auto add someone to a certain group depending on how much they donate (VIP, VIP +, etc). Does anyone know of a very good donation system that maybe has some of the qualities i just listed.
Thanks!

If you are willing to pay money look here for some good ones

Do you know of any good ones that are free?

if you dont have 5$ than thats kinda sad but i suggest this one http://coderhire.com/scripts/view/14 if you do, had absolutely no problem with it.

The only good donation addon is the one that doesnt exist