My mom goes to the used clothing store and buys bags of sweatshirts when they cost $2 a bag---she can stuff several sweatshirts into a brown bag. She cuts those into large squares of all different colors and makes a basic quilt. One of the churches in her town sends them off to overseas missions. The sweatshirts have been washed multiple times, of course, so they don't worry about shrinkage. Mostly they use flat sheets to back them, and I don't think they use batting. As you say, they aren't heirloom quilts, these are the type that get put to hard use for many different purposes. The church ladies will also set aside any polyester clothing items and make separate quilts of only all polyester fabrics.