I've decided different lines of fabric have different "feels."
Some seem to be "thicker" or "coarser" and the number of threads per inch seems to be less.
Others seem to be "thinner," and there seem to be more threads per inch.
I do try to keep the same kind of feel in the whole top. But that may just be a personal quirk of mine.
I have found fabric at WalMart that is decent - I saw some at a quilt shop for $9.00/yard (that was several years ago) that I wouldn't take home because it was flimsy - maybe a step up from gauze (well, I am exagerating a bit here) - I definitely remember it because it was in a color that I had been looking for all over the place.
So, for me, the price or the brand or store/shop is NOT the determining factor if a fabric is "good."