Need a work order / helpdesk app

Hi there - I wonder if you guys can help me. I need a simple work
order system in ASP or dot net to run on my webserver.

I need my clients to access the site, log their own calls and give a
few details. It would be good to get some stats etc too.

Does anyone know any apps that could help? I don't mind paying a
small amount for an app like this (=A350-=A3100).

thanks guys

Paul