Umm... if you look at how big a bite eBay and PayPal will take from the sellers of those fabrics, then you'll have a better idea of why the prices are as high as they are.
I mean, if you want to just get rid of your extra fabric, and don't care if you make any money on the deal, you could just donate it to a local charity. And it'd be a lot quicker and easier than listing it on eBay.
Personally, I sometimes buy on eBay, but as to selling... well, it just seems to be a whole lot of effort for, well, not a lot of reward per sale. Though I know several people who love to sell on eBay and do so quite successfully.