A full frame off 100 point concors show truck can bring close to $30,000.. but thats a dead mint, good as it was out of the factory and 100% original down to the valve stem caps on the tires.. cars like that don't see so much as a cloudy day once they're done.
I've seen really nice, clean AD trucks sell on eBay in the $18K range.. i'd say the truck you linked to is overpriced by about $10 to $12 grand.
Solid clean drivers sell on eBay pretty regularly for around $5,000.. these are usually functional, drivable trucks with decent paint (usually repainted) with little to no significant rust (may have filler or repaired/replaced fenders, doors, etc) and are often referred to as "old restoration".
A rough, but largely solid, mostly complete truck that dosent run can fetch $1500 to $2500
