As others have explained, DEMA is an industry show and not designed for consumer sales. Selling major gear items at the show is not allowed, however, you are able to order products (like a new drysuit) at the show and pay for it as well. Merchandise and small products (shirts, water proof cases, accessories, etc...) can all be sold. On the last day many of the exhibitors will liquidate what they have on hand (Trident sells all their accessories, UK lights sells lights). Most of the major products are not sold this way (i.e. you can't buy a d9 for 50% off on the last day) but there are a fair amount of deals during the final hours. This is even more true with companies who ship products -- it costs them less to sell at or around cost than to ship stuff back.