Amazon Marketplace is not an auction; you set the price of every item you list.   It would be similar to going into a large retail store and setting your unique product next to the product stock that the large retail store is selling.  If a customer picks up your product on its own or with other store products and checks out, the profit from that product sale is sent directly to you from the store.

Here's how it works:

• Once you list an item on Amazon Marketplace, it is displayed on the page where Amazon Marketplace would sell the item new.  The customer is offered a link to "More Buying Choices".  Items listed by individual sellers remain for approximately 60 days.  It is possible to re-list these items if they have not sold.  Items offered by "Pro-merchant sellers" remain until they are sold or unlisted.
• Amazon sends an e-mail to notify the seller when an item is sold and payment has been taken from the buyer. The seller is required to send the item to the buyer within two days of receiving the e-mail.
• Amazon deposits the payment or  earnings into the seller's Amazon Payments account.  These funds are transferred to your bank account on a 14-day cycle.