I have used sheets that I bought at Goodwill and they are really cheap, and soft. I also learned at Crazymomquilts that if one uses printed sheets for backing when beginning to quilt that you will see less of your goofs.
I have just finished my third quilt and used plain lime green sheet and she was right, I can see the errors. But it doesn't matter, I learned a lot from this and my next one will be that much better.
My granddaughter who helped me with this is quite happy with it and she doesn' t see the mistakes, just the beauty.
http://quiltingforfunandmorefun.blogspot.com One thing I learned here on this forum is that I must use more pins...