I bought eight clay pipes on eBay from a German seller about a year ago for about three dollars each. I gave a few a way and broke one. I smoke them every now and then. I like the taste of tobacco in them. As someone else said, they are especially good for trying out a new tobacco because they don't impart any taste to the smoke. They do get hot, though, and the bowls are small, so its not a long smoke. If I could find a clay pipe with a large bowl, I'd smoke it more often.
I also have a couple of Delft porcelain pipes. They look great but are terrible smokers. For some reason, tobacco has very little taste in these pipes and they get scorching hot very quickly, even though they are double-walled.