Trading kits has both traders paying to ship so I think it works out evenly. It depends on what you want to get rid of and how badly you want what you are trading for. As far as businesses they get a big discount for ordering in bulk so free shipping is an incentive to get you to order. As the saying goes, nothing in life is free. You are paying for the shipping, it is just built into the cost of the kits and not listed separately. E-Bay has the buyer paying shipping so you have to figure that into the price you pay. It all depends on how much you have in the kit and what you are willing to trade for. I enjoy trading and have found the majority of members here are great traders and I have picked up kits long out of production that I had been looking for in exchange for kits I would never build.