US wholesalers are pretty much like wholesalers anywhere in the world. The guiding principles of any traditional supply chain stay the same for it to work successfully. There are several permutations as regards what arrangement or contract you may want to enter into with your wholesale supplier. This in turn will depend largely on your fund availability, risk taking ability and several other factors. Be sure to draw up some kind of business plan with a financial forecast before you jump in. There are several fixed, as well as variable, costs relating to sales that can eat into your profits.
A casual read of any dropship review will introduce you to the basics of this model and the advantages as against vanilla US wholesalers. A new retailer gets to save on warehousing as well as shipping costs not to mention the fact that he need buy only what he or she has sold. Genuine dropshippers work with even single package deliveries but that is not always the case with middlemen posing to be dropshippers. The only big risk is loss of control. Not only does the retailer end up entrusting his or him client list to a third party, they also never know what is being sent to the customer. Product exchanges and return logistics can turn out to be a nightmare.
In case you are planning on buying from US wholesalers and sell on an online forum like eBay, it may be a good idea to go over the various eBay tips given. Not only do they help you avoid fraud but also give you information as regards the way the selling platform operate. Each market is different and it is best to work within the rules for maximum benefit.