It's good to do some research. I've used old parts, Sturmey Archer AW and Bendix Red Band, because it's a hobby. But people are getting wise to the value of those parts, so it can be hard to find bargains. On the other hand, a new hub isn't all that expensive in the grand scheme, and then you know exactly what you're getting and whether it has all of the needed bits. (Including the correct number of spoke holes for the rim that you want to use).