i use both paper and cloth depending on the application and the stuff that stewmac sells is good, but also pricey. cloth is usually used around a humbucker or single coil, where paper would be around the individual coil of the humbucker
You can get the tape on Amazon as well. There are different widths available so make sure you know what width you need.
StewMac's prices are a bit high, but you'll get great quality. But at about $6 you get a lifetime supply. You'd spend that much on a hamburger and it will be gone in a few minutes.