I once tried to sell a car like this. I put an ad in the paper that said, say, $6000 and dropped it in price over time. It didn't sell. Years later when I went

I once tried to sell a car like this. I put an ad in the paper that said, say, $6000 and dropped it in price over time. It didn't sell. Years later when I went to buy a house the real estate agent explained to me why. The market for houses (and presumably cards) include lots of people who are watching and waiting for months or years to buy. They get into a steady state where they only look at new listings and ignore the ones they've already seen. So if your house or car doesn't sell relatively quickly, you move from the seller-arrival queue to the buyer-arrival queue. Which takes disproportionately longer and it's likely that you won't be getting the best price for it.