I just bought a 2005 f250 crew cab 4x4, single axle, no air supports, never had camper on it. What size camper will fit it?

Depends on the bed size. Is it a 6 foot or 8 foot bed?
Gary

If he is in the same situation that I am in with the F150 Crew Cab my bed is 5 1/2' long. I am looking for something as well. My deal is I need to pull a full loaded bass rig behind it as well. I am not sure what options I have other than buy a new truck.

It looks like the Lance 825 might be a fit:

http://www.lancecamper.com/truck-campers/825/index.html

Check where the center of gravity lines up with your truck. It should be in front of the rear axle. The Lance 825 looks to have a 45" C.G. (that's 45" from the front of the truck bed back).