You can't.
http://store.itaser.com/shared/Store...unt2=752524971
This is if you buy direct you could probably find them cheaper else where.
They command a shocking price for sure. As much as a quality handgun but you get a much better less lethal tool over the OC.
These are just less lethal tools though and my post are just about the effectiveness of them. IMO some form of unarmed training and a handgun/knife are the bare essensials for defence everything else is optional.