There are several different ways to price your products online. However, it does tend to be fixed price versus auction.
A fixed price expedites transactions and increases overall sales volume, especially if coupled with online payments. Customers don't have to bid and wait or haggle over a price. The price they see is the price of the item.
Upside: Fixed price is useful for common items that have an established market price, particularly product accessories and add-ons sold in volume. It also proves quite effective during the holiday season and other periods of intense buying, when shoppers do not want to wait for an auction to end.
Downside: You do not know exactly when you will sell your products, ...