" Many auction houses make a buyer put a small deposit to bid on a car. I see no reason why eBay can not require a bidder to leave a small deposit to show that they have an interest in really purchasing a car." Let me start by saying I do NOT condone recreational non paying bidders.
Next, you are exspecting Ebay to be the same as an auction house or vehicle auction, it is not.
It is an On line venue, period.
It is no different than if you place an ad in the newspaper and get calls saying the person will be over to look at and buy the ride and they never show up.
Ebay is not going to scar off potential buyers by asking for a credit card and dinging the card for a deposit if the bidder fails to follow thru. It simply is not going to happen.
There several things you can do to cut down on your non paying bidders.
1. require immediate payment Link
2. screen your bidders as they bid.
This means as you see a 0 or low FB bidder, go look at their bidding history. Are they bidding on 6 similar rides as well as your? If yes then cancel and Block their user ID.
3. For 0 or low FB bidders , pull their contact info and give them a call to feel them out.
If the phone number is invalid, then report it, cancel and block.Link
Call the buyer and feel them out. Do they sound serious, ask them if they have any questions regarding the vehicle you could help them with. You can tell if a buyer is serious or just playing during a quick phone call.
4. Set your buyer requirements/seller preferences to exclude those who do ot meet your requirements.
5. 0 FB bidders who are registered in a foreign country when you only sell to USA bidders, can easily be found by taking a quick look at a bidder's feeback page and or setting your buyer requirements.
Non Paying bidders can not be totally eliminated, but sellers can reduce the number by using the tools Ebay gives you properly.
Ebay now allows you to file the UID(Unpaid Item Dispute on day # 4 after the auction has ended, instead of waiting 7 days post auction.Link
Pick up the phone , call the buyer and see if they intent to pay or not. If it is clear they will not, then go to your next highest bidder and Offer the Second Chance Offer via Ebay's message system.Link

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Proud Mom