Target has 100% cotton sheets that are wonderful and soft, I watch for them to go on sale and stock up. I read somewhere that the higher the thread count the harder to quilt. I've never found 100% cotton at Walmart, they have some that are "cotton rich", but they feel like they are a mix. I also look at Ross, Marshalls and TJ Max they have some cute prints that are perfect for children's quilts, but you have to be careful and read the label, make sure they are cotton.