In the southwest you can score a K-10 for 500-1000. Condition varies, most have sat outside for years neglected like mine did.
Of coarse the trucks that have had some work done are worth more, good paint and interior bring up the value.
Some pickups like crazy4offroads K-10 look rough but have a incredible amount of fab work and premium components that would value it a **** load higher than just a regular K-10.
To put it as basic as possible if it has faded paint, worn out interior and a complete drivetrain with an engine that cranks over it will be worth 500-1000 here.
I found a really nice special edition K-10 spirit of 76 that was un molested with a 400. this truck was complete in every way, a few days of buffing the paint and this thing would have gone for many thousands..... The guy only wanted 700 bucks for it.
These pickups are becoming more popular, they are going up in price in Reno. I keep seeing more and more on the road, the 67-72 chevy trucks are becoming rare so our square body's are the next trend.