if you wonder why I have brought this up, well I know a lot of people who use Ebay to help with their income to buy extras for their hobbies etc, but the number of sales they make is not enough to justify a business, anymore than going to a carboot everyweek.
If you look at the maths, as I have done Im beginning to wonder why anyone bothers listing on ebay.
Potential costs
List an item of 99 pence ---       0.10
If it sells                       ---       0.10
Paypal fees if it sells      --- 0.26      (you have to offer Paypal, who also charge a percentage on postage costs)
Postage fees             -- 0.41            (assuming small letter size item)
Net return -- 0.12
Is it worth it ? 
Nope