I've always wondered why we dont do that. We do it on my treasure hunting forums once in a while for equipment and it seems to work out good, you save a little. It all depends on our sponsor's profit margin's and if they could actually get a big enough discount on the item . Keep in mind that on a site like this you'd probably be talking 50 or so people maximum getting in on a group buy for say like a set of pipes or serval cylinders and I doubt there would be much savings. It also takes alot of advance notice to get people in on it so the sponsor can know how many to order and then not get stuck with a bunch of inventory he has to sit on. It has to be a pay in advance type a deal. On the other hand, for short production run stuff its the best way to get a good deal on it.