I have a couple of relatively inexpensive muslin backgrounds made by Impact that I've been using for more than 5 years now. They came in kits (I bought two kits, each with one backdrop, in light blue and dark gray) that included the backdrop, the stand to mount the backdrop on (tripod and crossbar) and even a folding bench for the subject.
The backdrops are stored in nylon bags, and the way they shipped (and about the only way to get them back into the bags) is crammed in, which creates a lot of wrinkles, which I believe is intentional. It creates a "pattern" or "texture" in the backdrops, and I can control the degree to which this is visible in the portraits, based on distances between camera, subject and background, as well as lens aperture.
Most of the time, I place the backdrop far enough behind the subject that it looks "blurry smooth," and I light it with a dedicated speedlite; I adjust the intensity and spread of the light on the backdrop to achieve the desired look. Very pleased with the results.