I experienced "winning" bidders who didn't pay up, I bought from people who changed the deal when it was time to complete the transaction, etc.
The clincher was when I sold and shipped a $250.00 item that the buyer claimed he never received. I made the mistake of not insuring the delivery.
I asked the buyer to be patient, that I had, indeed mailed it and that it must be delayed somewhere; but the response was not only rude but increasingly threatening, demanding a refund, which I finally reluctantly sent.
A day later eBay advised me via email that the purchaser's account had been hijacked, and I had been scammed out of $250.00+product.
eBay offered no further assistance.
All that’s a good reason NOT to do E-Bay as I see it. Better go to your local flea market and have at it! “Bird in hand is worth more than two in a bush!”