You can sell anything you like, although the best items are computer and electrical equipment.
Contact local shops or the web to obtain stock. Stress that not only will they sell their goods quickly, they'll get free advertising too.
Using a Web site you can display details of goods, along with a picture, the last bid received, the amount the bid can be increased by (proportional to the goods price), plus the cost of sending the goods to the winning bidder.
Accept new bids by e-mail and update your site accordingly. Set a two-week limit per auction, so that the highest bid at the end of the fortnight gets the goods.
You can then pass on the details of the winner to the shop, who will send the items out and pay you your commission (at least 10 percent of the sale).
Do not be scared of the competition. Its a big old world out there, and there is always room for more good competition. Was Honda put off by the fact that Ford had been making cars for ages?