Originally Posted by GingerK

I also get sheets at thrift stores--both flannel and 100% cotton. The hardest thing often, is finding and deciphering the label. Mine also immediately go into the laundry.

The most inexpensive quilt I ever made consisted of two thrift store sheets (one for the light colour in the piecing and one for the backing) and a meter of wide backed batik. Here's a picture.