I know that if you get one built, it costs an arm and a leg. I am speccing one now, and even through my dads company (who are making it for me) it is about $300AUD in materieals and another $500AUD in labour.
I was expecting close to 1k budget. And I'm skeptical in buying a used case as they have been used and abused. And require quite a bit of maitnence to keep going.