You might try
Fabrics.com
Sign up for their e-mails which come on a weekly basis. Sales all the time but if you don't order the first time you see it, the fabric may be gone later (don't ask me how I know!).
In addition to quilting fabric, they also have fabric for apparel, home; they also sell notions and patterns.
They're quick to ship and I've never been disappointed in anything I've ordered.