Hello Joe S, welcome to the board.
The prices for certain cars has fallen a little recently do any number of reasons (recession, time of year, etc.). If you have good negotiating skills, you can pretty much make any deal you want.
Since it sounds like you’ll have to tow or flatbed the cars to remove them from the property, make sure you factor that cost into the offer.
Does the seller have any motivation to get rid of the cars? (Moving, property has to be cleaned up, divorcing, etc.) If not, don’t expect him to accept your first or even second offer.
Based on what you’ve described, I would start the bidding at something like $1,000 or maybe $1,500. He’ll probably balk at that because he things the GTO is worth that or more by itself
, but then you can ask what he thinks is a fair price. After that, the negotiation can begin.
By the way, some people would rather let their cars rot in a field than sell them. It’s the old “gonna restore it someday” philosophy, and it can be a deal killer. If that’s the case, you may have to just walk away and watch the cars continue to rust away.
Good luck.