I have had very good experience buying online from
http://www.aaaquilterssupply.com/index.html
You can see from their "Home page" that if you buy over $100 worth of fabric the shipping is free. It works, I live in Alaska and they've shipped to me several times for free for my purchase over $100.
Also, their customer service is wonderful. Selection is a little limited sometimes, but they have great sales. I can vouch for them shipping top-quality fabric and free shipping over $100.