To elaborate on the above points, the hardest part of drop shipping is finding suppliers. Take your time to find A. find suppliers that are offering decent discounts and B. suppliers which will give you flexibility around returns and other customer service.
Although it is important to understand drop shipping, drop shipping is simply:
1. Customer makes purchase on eBay
2. Retailer locates the purchased product by inventory number on the manufacturer's drop shipping interface (avoid drop ship programs without solid interfaces, otherwise you will have a nightmare when it comes to returns)
3. Retailer provides drop shipper with eBay customer's name, address and personal details.
4. Drop Shipper sends ordered product directly to eBay customer billing the retailer at the same time.
5. eBay customer obtains purchased goods from drop shipper, some drop shippers masque the goods to make it appear as though it came from your website.
In the above example you may ask yourself, so what happens if a customer wants to return a product? This is really up to the drop shipper, but you MUST understand that you lose control of the return process as the physical goods must be sent back to the manufacturer as you yourself can not facilitate the return. Sometimes it becomes messy as a customer may ask why they are sending the product back there and you may have to manually arrange for shipping costs both ways!
So in a nutshell, drop shipping is selling stock from someone else's stockroom and your most time should be spent researching your potential partners!
I wrote an article on finding the best drop shippers, you can read it here: http://www.goarticles.com/cgi-bin/showa.cgi?C=1885779