I'm a big fan of Backside Fabrics too.
But if I need a lot of one fabric, or can share with a buddy, Textile Collections (fabric4less.com) is the BEST place to go. You can buy really nice 108" wide fabric for as little as $5.75/yd.
Right now, they have lots of wide batiks on sale for $8.75/yd.
The catch? You have to buy the whole bolt. This place only sells by the bolt or by flat folds. They also have some fat quarter bundles.
It is a wholesaler, but you don't have to be a retailer in order to buy there. You just have to register (for free) and then log in to see (and get) great prices on everything. They have lots of name brand fabrics.
I have no affiliation or family or friends there, I just like 'em. They also have great prices on by the bolt 44"- 45" fabrics too.