I buy most fabric at Walmarts and Hobby Lobby. I give most of my quilts away and it is goos quality. I go by the feel, I have not been unhappy with it. I only buy 100% cotton.
I have bought from a popular online store and their quality is good also. Last time I got a lot more than I wanted.Online says yards but it is cut at units and that was twice as much. Needless to say I will only buy from above sources. Colors are not the same as in person.
I only pay where the prices meet my money. Lots say to buy from local quilt shops but that is more than I want to spend. I don't see where it is any better quality.
I have made over 136 quilts.