I over paid for mine a little, a little more than $6500 BUT it was a clean bus. Had all the options/extras I wanted and actually included a few I didn't need.
I ended up getting a 1995 Thomas Build RE with a mechanical Cummins 8.3 with an Allision MD3060 with the 6th gear unlocked. It has a huge basement!
It also comes with a webasto heater preheater and automatic chains.
Just search until the right bus finds you. Some folks search for months or years, so find their bus in a matter of a month or so. Don't let anyone rush you or make you think you have to take a certain amount of time. I have already had one seller think I acted on impulse but that's just because I didn't buy his bus and found this better option.
Move at your pace and your bus will find you.