I love going to creative reuse shops to buy my fabrics and sewing notions. It's cheap, more sustainable and you help the community too. I'm going to list the ones I've visited and would like to visit if I'm in the area.
Map
Located in Oakland, CA. You pay fabric by the pounds.
East Bay Depot for Creative Reuse
Located in Berkeley, CA. Super cute and quirky store with lots of fabric selection!
Reuse For Arts & Crafts
Located in Austin, TX. I got a lot of cute fabric here and most fabrics cost $3/yard.
Austin Creative Reuse Center
Located in Austin, TX. A small shop full of fabric and trims selection.
USE2 Neighborhood Reuse Center
Located in San Antonio, TX. A small shop but filled with lovely arts and craft supplies.
Spare Parts Center for Creative Reuse
I'd love to check this place out. I've heard lots of good things about it.