So your first sellings will teach yourself how the process works, how shipping works (printing postage using paypal is the easiest way for most goods), and the main goal here is to recieve positive feedback. So the small margin of profit here is not the point. Trust and reassurance for future buyers is.
RETAIL!
Retail has sales going all the time. The trick here is to find something that is deeply discounted and make a profit off of it. Some great examples of this are Ross, Marshalls, and TJ Maxx. I have made hundreds upon hundreds of dollars from buying things at Ross and these other stores and reselling them for profit on ebay. Specific example: I go to Ross and find Nike Indoor Volleyballs which still have the MSRP price tag of 60 dollars on them. They only cost 7 dollars each at Ross! Needless to say, I bought all 6 they had in stock and made a hefty profit off doing almost nothing. Another great thing about retail stores....Almost all retail stores have a return policy!!! So even if your items dont sell at all, just hold on to the receipt and return them! You'll only be out about 2-3 bucks for the listing fee, which is nothing compared to the profits you will make.
One NECESSITY is to check the final prices of sold items which you find in retail. You can either 1) Buy the items at the store and return them if the prices online are even lower than you bought them for; or 2) Write down a list of all the items you find in the store with the prices and check them on ebay's Completed Listings under "Advanced Search". This will also give you a good idea as to how much money you will make.
This costs nothing out of your pocket. Simply find a deal anywhere (i.e. Newspaper Ads, Internet prices, local stores) and create a listing for that auction. Make sure the item will still be available for that price by the time your auction ends. This way you can make profit off items you don't even have! Once the buyer pays for your item, take his money and go purchase and ship the item. Leaving the profit for yourself!