Freelance Project

I own a php webstore that has been online and receiving orders for over a year. I want to add a simple feature, where a user can have an option to bid on an item (a live auction, where bids are placed and seen without refreshing the page) instead of just buying it! I also want this feature to be selectable! In other words, the admin area needs to allow me to have the option on which items I do or don’t want to be available for auction as well as for sale! It also needs complete comtrol over pricing, reserve prices, winners, etc.