Don, you have to take a couple of things into consideration, first, Alex and I are way out of the "Free Shipping" offers or promotions that come with sales at Rockler, Woodcraft, Amazon etc, so we have to pay for shipping, and dearly, so we have to take that into consideration, sure a self centering jig is cheap, only $20 or so, but the shipping is going to be $40. It may sound strange, but I'd much rather buy a tool that is of higher quality and versatile and pay $100 and $40 shipping, than buy a cheap tool that is only good at one thing and pay $20 for it with $40 shipping, like I said, it might sound strange.....
Have you watched the YouTube video of the Joint-Genie at work? I really is dead simple to get perfect joints every time, also, we are in Japan, and use them millimeters and such, so a dowel it jig, in inches is not much use, when I cannot buy dowel locally in inches.
All of those reasons were for me good ones to buy the Joint-Genie, but they may not be good reasons for you. Not all of the members here are from the US
Vaughn, I agree that I could most likely make a good copy of this item, but by the time I did that, with the steel, and such, and the time invested, I'd be only a little ahead of the cost of the Joint-Genie, and I'd be stealing someone else's good idea, that certainly may not bother lots of guys, and I guess stealing may be a little harsh, as they are only making things for their own use, not selling them, but there are some things I could not easily copy, one is that the bars of the jig are hardened steel, I guess I could dig out the forge and go through all of that, but again it adds a lot of cost and time to the process. With regular old cold rolled steel, in time, the accuracy would suffer and then where would I be, my work will have been dumped down the drain.
In this case, I felt it was much better to just pony up the money and buy the jig, I'm sure I'll be using it and enjoying it for a long time to come.