Thanks. It's in the 'For Sale' section of the site if someone is interested.Santa Fe is right, in that the "value" of the set is what someone is willing to pay. I personally wouldn't value it at $500. Maybe half that. If they are custom painted, they might fetch more than that. But they base kits are inexpensive Athearn models, and old ones at that.
But that's just me. Try it and see what you get.