I buy $8/yard fabric. It works better for me.
I did a quilt project with students where I told them to go to Joanns and get a few fat quarters (just making blocks). I brought in my scraps to supplement. The students (most with no quilting/fabric experience... ever) commented that mine was easier to work with and felt "different". For me, the Wal-mart one feels lighter, not as solid, and when I poke a needle through it, the hole stays. I like my more expensive fabric