I have a gigantic stash, and I'm mostly working from stash now, but I buy yardage for borders and backings. There are wonderful sales and incredible online sites with low prices on quilt shop quality cotton.
I often buy from the back room of my LQS where the sale yardage is kept, or online at www.thousandsofbolts where most fabric is around $4 a yd. They ship it the same day and it is wonderful stuff. No affiliation, just a happy customer.