Thinking of selling my stone stock barn find 1 owner 71 340 Duster

More than enough. Couldn`t stand to see it just rotting away. The other 2 that offered me money have since bought a Demon and the other bought a new Charger. Guess I could list it on ebag and stop the auction if I don`t like what it looks like it will bring. I can also just keep it and steal the shows with it just the way it is. Snow tires and all!

Worth is subjective and is irrelevant in todays car market.
From a strictly numbers standpoint, it's worth what you paid plus the amount you choose to mark it up and sell to the next buyer. The "mark up" doesn't have to have any rhyme or reason- just look on ebay (for the reasons pointed out above among others.)

Kinda like what car salesman do.

Me...I would tell any buyer how much I paid, put into the car and how much I'm looking to get. No need to beat around the bush.