I've found that the price of the fabric is not a guarantee of quality any more than the type of store purchased from.
Quality is determined by several factors, most of which have already been listed. To me, feel is the important thing. If it meets all the other signals of quality and doesn't feel good, then I won't buy it. And if it feels good and may not be quite top quality, but the color/pattern is what I'm looking for, then so what...it feels good!