Well, strictly speaking, I think you get what you pay for. Having said this everyone has a different budget and makes quilts for different reasons. Also there can be exceptions to that rule.
I buy most of my fabric online. The prices are good and the brands are what I like- Moda, Kaufmann etc. Once in awhile I buy in quilt shops but rarely. I used to a lot more. I think they are out-pricing themselves these days.
I personally have never been disappointed in my online purchases.
My philosophy is for all the work that goes into quilt making I want the best fabric possible.
I realize this doesn't work for everyone. For me it does.