The following is excerpted from Clifford Mishler’s Coins: Questions & Answers
Selling your coins yourself in online auctions can be fun if you have the time and talent to do it. This typically requires some skill with scanning or photography (buyers like to examine potential purchases). Each auction site has its own rules and policies, commission rates, etc., that you should read carefully. When it comes to transactions, as always, be security-conscious—for example, you might want to rent a Post Office box instead of using your home address, and you should insist on full, guaranteed payment before you ship any coins.
You can also use the Internet to sell your coins at a fixed price, through a bulletin board posting or other announcement.
Any online sale to the public requires you to take on responsibilities similar to those of a retail coin shop or auction firm. There is work involved, but the experience can be enjoyable and profitable.