Flip job!
The asking price for a car has nothing to do with what you paid for it. I rarely sell cars, but when I do, I think it stupid if a buyer asks me what I paid for it. That is usually apples and oranges anyway if I made major repairs. A more relevant question would be for me to ask, "what alternate cars have you seen and what were their condition and prices?"
I doubt the ebay guy bought the car just to flip. If so, why sit on it for 4 months? The $12,500 is a "Buy It Now" price for somebody that really wants it. It is in FL now, so maybe worth $500 more than in TX. If visiting CA or AZ from the East and had more time than money, it would be smart to buy a reliable car there and drive it home. A rust-free car might be worth $2000 more in the East, and you would be doing the hobby a favor. Call it "flipping" or "smart". Free enterprise, trust the markets.