A twin fitted sheet works great as a bottom sheet, and these can be bought alone at walmart for $3. that's a poly blend. any sheet will work as a top sheet. if you want 100% cotton, or much better quality (dyes, etc) the price will go up.

also, at massagewarehouse.com, and probably other massage supply houses, they sell sheet sets that are other than flannel. the one i just mentioned sells polyblend, as well as 100% cotton "jersey" sheets.

and, you do not Have to use a fitted sheet for the bottom. a flat sheet will work fine, although it might bunch up a bit. if i use a flat sheet on the bottom, i just tie knots at the corners, and that makes it work just like a fitted sheet.

Best,