eBay is one of the most popular online marketplace in terms of traffic and revenue, anybody can do a business son ebay. You can start by creating an account and then simply start listing your product by clicking sell option located at the top of eBay's homepage. You have to ways to sell your product, one, through a fixed price and another through an auction. Choose the one that is most suitable for you based on the item you want to sell. Provide as much details about the product as you can, optimize your product listing for ebay internal search. If your product needs shipping, you need to provide shipping details as well, for instance whether you offer free shopping or buyer has to pay for shipping