I personally, never buy fabric at either WalMart or Joanne's. I only buy from the quilt shops or on line at the quilt shops. There is a lot of difference in the quality of the fabrics. Good quality is also alot easier to work with.
I am also cheap so I always check out the sale tables. There are a lot of great buys online. My favorites are Hancock's of Paducah and Quilt in a Day. Great buys and a huge selection at times.