Cheap white sheets

[bitchtransformr.livejournal.com]

I seem to remember someone posting a while back, trying to find a way to get a large quantity of fabric for really cheap. They mentioned that you could get old hotel sheets. Now I need to get white sheets (for a backdrop) really cheap. And I was wondering, how do you go about getting old hotel sheets? Does every hotel sell them? Or was that just a specific hotel in a specific town that sold them?