Hi Tasha....I have a friend who collects sheets for me to use on the back of quilts. Just make sure the material is good and not 'worn thin". I machine quilt and love having the large sizes of sheets to use. I often am given sheets with pretty patterns printed on them. They look great for the backing!
If you can find some people who collect items for charity (clothing, kids stuffetc) they likely will also know someone who can get you sheets. I have also heard of contacting motels and hotels for their used sheets...
Good luck with great savings!!!