I like Hamels, SewSisters, Clothesline Quilts, Country Clothesline, Thread Count Fabrics.
SewSisters have a clearance section at $9.00 a yard, and I've ordered from them often. I've never been disappointed.
I mostly order fabrics on sale from the above stores. Quality is very good.
I used to order a lot from the U.S., but I found it increasingly frustrating to never know in advance how much I'd end up being charged. Sometimes duty is charged, sometimes not; sometimes brokerage fee, sometimes not.
I must say though that from time to time, I will order from Equilter in the U.S., and so far have never been charged duty and brokerage fees. They have great sales at 40% off, and that's when I order. They will also sometimes offer 50% off shipping for international customers.