Fabric.com has great sales and free shipping at $35 so you can buy more fabric. 
I love the free shipping.. and wow do they have a selection. Now they have a "yard sale" and a number of fabrics where the more you buy the cheaper it is (buy 3 yards and get a price break - which is good if its a backing fabric or something you will use alot of)
I like them too, but they don't have the selection that Fabric.com does
I have bought alot of fabric at Amazon too!