I was in the same mind when I started quilting, I don't have a Walmart here in the UK, but I learned over the years by the touch and feel, lack of fraying etc; what fabrics I liked.
I now buy all my fabrics from
http://www.thousandsofbolts.com/ as they sell only top quality known quilting fabric manufacturers at amazing prices, so much so that even with postage is it cheaper for me here in the UK, where the prices at our LQS are shocking :shock:
Give it time you will learn your preferences.