in response to your post, my company acts on behalf of many companies in generating leads for them, we get paid in two ways on and individual basis for every lead or the one we prefer is a conversion for that conversion we get a substantial amount of money. we also run sever shops computers, animal health produts and so on. to be successful you need to get the site seen and also to be in control. on two shops we actually do nothing but promote the site with the engines, all orders and shipping is done directly with the client. however be carefull if you are proporting to sell the products make sure you are not liable for refunds or damaged goods.
by the way dam good way to earn money after the initial build cost everything is profit set another company up and enjoy the pension