I purchase fabric on ebay all the time the only problem doing this is you never get to feel the fabric for the thickness and quality of it. I have had a couple of seller on Ebay who mislead the fabric by making buyers think the fabric is actually thicker than it actually is they do this by putting a piece of thick cardboard in between the fabric and wrap fabric around cardboard then take the picture.
It is annoying but feedback is there for a reason the sellers are doing themselves no favours by doing this as feedback reflects they fabric.
I have regular good fabric sellers which i use regularly