look for sellers feedback, at first buy fabric known to you,it is difficult when you can't actually see well and certainly not touch which I find a great drawback.
I have bought lots from ebay and been very plsed,did once have a stiff fabric but when washed softened; I buy q/tops and have had no grat problems except two where one had a tiny hole in and other prick blood but the selers were v honorable and refunded my money.