I buy and sell a lot on eBay. Like Ruth said, the postage can be bumped to make up for a cheap price on the item. If the item (fabric) is a good price after combining the sale price and shipping price, you may wanna go for it. You can get a lot of good deals on eBay.
Also, as Ruth said, look at feedback. I will not bid on anything from a seller with less than 98% positive feedback. Make sure they've sold more than 1 or 2 items, too.
I recommend registering with eBay. It's a lot of fun. It really is easy.
I did see Elvis fabric at a WM a while back. Not sure if it was the same you mentioned, but they had 2 or 3 different kinds.