I when I started stash building,spent quite a bit of time "researching" online quilt shops; many have discount fabrics all the time.
try: Quiltshops.com-there you will find dozens of shops that are organized on this one site. you can also do a comparison search if there is a specific fabric you are looking for.
Also, try Fabric.com. This place has great sales,wide selection, and free shipping for orders over $35.
W/ the price of gas and distance between fabric stores, I often find that I do much better online-