Well, what do you want to sell?
It's always best to try and sell something that you have knowledge about or an interest in. This way you will be better equipped to answer questions that might arrive about your product. Also if you have an interest in the product it makes it more enjoyable to work with that particular product...
Next keep in mind that ebay is a BELOW WHOLESALE market. You will never make a profit on a wholesale item on ebay. People who do are people who have very large buying capital and are purchasing very large quantities of items in order to get a lower 'price per unit' . The larger an order they make the lower price per item they get.. For example, if you contacted a wholesaler and asked for a price on 10 dvd's he might say 5 dollars each. But if you asked for a price on 100 dvd's he would probably say 1 dollar each....The larger quantity, the lower the price..Most sellers who sell wholesale are buying hundreds if not thousands of items at one purchase..
That being said, you should probably look into buying items from 'liquidation, closeout and surplus' dealers..Buy by the pallet load or truck load if you can afford it..
If you are just starting out I would suggest trying to buy just a pallet load fro a few hundred dollars. Purchasing that way you will be getting the items at way below wholesale prices....actually pennies on the dollar...This way you can beat the selling price of someone who is selling at wholesale...
Check out sites like liquidation.com, surplus.net and sites like those to get pallet or cases of goods...
viatrading.com is a good site with low shipping cost also...