I find 100% cotton sheets for backings at thrift stores and garage sales for $3 or less. My fabric stash is large and most of it is from thrift stores, I rarely pay more than $1 a yard there. I still do buy some fabric from the big fabric stores but only on sale. I brought home at least 40 yards of nice fabric from our vacation in Tacoma, great stuff at Value Village and a store on 72nd Street.