I agree that the price of a decent D60 is way too high. That being said, I got mine for free. Wanna know the secret? Don't look for someone selling a D60, look for someone selling a 4x4 F350.
I bought a 91 for $800 bucks, running well but rusty. It was an old service truck. I pulled out the front end, and then sold the rest for $800, and probably could have got more. The best price I could find on just a D60 of any year, any condition was around $1300 with no knuckles. Just what they're worth around here, I guess.
Oh yeah, and it took me almost 3 months to find exactly what I wanted. Just goes to show that if you be patient then you'll have a better chance of finding exactly what you want.