If you know how to tell good quality fabric from poor quality, you can find it at all of those stores.
Joann's has a lot of poor quality fabric but also carries some, that's decent. The same is true of WalMart. That said, I dislike Joann's because they've raised their prices and the 'good' stuff isn't as easy to find. In addition to that, they mark the best fabrics down a few cents, so that they won't qualify for the sales coupons. That aggravates me.
Hobby Lobby has mostly good quality fabric and very reasonable prices, with their 30% off quilters' cottons. Many of their fabrics are LQS quality but at a much better price.
My favorite place to shop is now
www.thousandsofbolts.com. They have LQS brands, along with many others and most are just under $5 a yard.