[Priusjames]

Buying is faster and easier (can't really go wrong with Incra, I'll have to look at the I Box), and there are also a lot of make it yourself jig plans online. Here's the jig I'm building, with adjustable finger widths using different (wooden) drive gears. I like gears. I paid a few bucks for the second/updated plans, but this one is free:

http://woodgears.ca/box_joint/jig_plans/index.html

Poplar is cheap(ish), and building jigs is fun! Just wanted to share...