Since I've just started I'm not sure all the great places to go... I have been to Wal-Mart and while their fabric is cheap, they don't have a good variety.
I got the fabric for my baby quilt from Joanns in Murray (off 5400 S and Redwood). They have a great collection and it was okay priced. It cost $3.99 a yard.
Good luck and let me know if you find a better place for fab!