I think I saw it mentioned here or on another forum that there isn't much margin in Maxtrax to offer a group buy. I seem to remember a vendor saying that if they could get it organized they might be able to get a $20 or $30 price break.
One of the Toyota forums had a group buy on MaxTrax and I got in at the very end. Price was pretty good, more than $20 or $30 off, but I don't remember the exact price. I bought two pair for my main truck and can confirm that they do work. I like them enough that I'd buy another pair for the other truck if there is a new group buy.