Here's another way for buyers to con sellers in eBay;
Let's say I am selling a purple widget, and I set it up as a 99p auction, but with a "buy it now" of £20.
So, a buyer comes along and makes a 99p bid. The option to "buy it now" disappears. That buyer then contacts the seller to offer to buy it now for £10.
How many sellers have fallen for that con trick?