If you check the selve edge of the fabric. The side, where it doesn't fray, there is usually the makers name of the fabric. Ebay is quite a good guide, I find, to the value of something like that, but you have to follow the sale by "watching" it right up until the end.

A charity shop is a good place to off load stuff you don't want anymore, if it is too good to throw away.

Loo