Where do you live OP? I know here in the South everyone wants way more than what the vehicle is actually worth. If it's a Z71 package Silverado, you can expect a asking price of at least $9-10K usually more, reguardless of year/ condition. Matter of facts, all trucks you can expect to pay for. V8 Camaro's and Mustangs fetch a pretty penny too. It's tough to find anything that's a good deal. Everyone thinks they have more then what they do.
Do they have Kelly Blue Book down there, lol? I'm in Pennsylvania, and off the top of my head, I know 88-98 Chevy 1500 4x4 trucks, which I deal with a lot, even flipped a few, go for $4000 in mint shape with new tires. Decent condition trucks go for $1750-2000. I refuse to pay anything more than blue book. For as fast as I go through vehicles, it isn't worth it to me. I'm usually driving a 'new' used vehicle every 6 months, so I don't bother paying more for a 'nice one'. I regularly see people ask up to $5-6000 but I've never heard of anyone getting that much. The downside of shopping for used cars here is there is no such thing as 'rust-free'. Heart of the rust belt, in PA most cars and almost all trucks that are older than a year or two have some sort of body rust. PennDOT's insane overconsumption of road salt and our horrible roads and their many potholes are the biggest contributors to this problem. Rust is a regular thing here especially on trucks and I honestly don't think most people are even bothered by it as long as it isn't frame rust. The silver lining in my situation though is body rust makes it easy to talk down prices on vehicles, so I can buy them cheap, then drive it for 6 months, fix it up a little, and sell it on for a profit and repeat the process.