I have fabric from several sources; goodwill, old clothes, local quilt shop(sale) friends; garage and estate sales.
Just make sure everything has the same content for washing.
Also Joanns has coupons and alot of local quilt shops will honor those coupons as well. And don't be afraid to ask local shops when they are having a sale. But usually you can't use a coupon with a sale item.
I save all scraps and use them for potholders as little gifts. And now love the idea of mug rugs !
Enjoy the hunt.