If you google cotton percale sheets, you will come up with lots of companies who have them. I love the ones made of Egyptian cotton and a 600 thread count. They are NOT cheap but they last a long time. Do not buy sheets with any kind of polyester in them unless you like sleeping on plastic bottles, because that is polyester. The fabric will also pill and those little balls are horrible to sleep on. I can't even wear polyester in the heat of the summer in blouses, etc. Even those sheer lovely blouses that say polyester voile, like wearing a wool sweater.
So I look for cotton or silk voile, even some catalogs are carrying them again now. Satin polyester is the same, HOT!
Since I sew, I look for cotton, silk or lightweight cotton knits that have maybe a 40% poly. Since quilters know about the hand of a fabric, I too buy sheets singly. Your touch can feel the softness. I wash them before ever putting them on the bed, if they don't feel right, return them.
Here is the definition of percale:
http://www.dictionary.com/browse/percale
Believe it or not, one said cotton or polyester. Don't believe it for one moment, my great grandmothers made sheets, 100 years ago, and they used cotton percale. Polyester wasn't even heard of then. I think one store was Bed Bath and Beyond. I always buy my cotton percale sheets at JC Penneys.