Auction Website

I am looking into creating a website that is similiar to flippa.com. It would be an auction website, capable of realtime bidding and tracking of domain names, and websites to start. Also needs to do all of this by itself without a person having to do it all. Would need a backend so users could have an account. It would need to be able to process payments, as it costs say $5 to submit an item for sale, and then I would get a Percentage of the sold price, etc... The way flippa works, payment is through paypal or credit/debit card I believe. It needs to function very well. It doesn't have to look exactly like flippa, but needs to be laid out very nicely and be very user friendly. I will have the domain name. I am not necessarily in a big rush with this, I am trying to get things planned and researched. Please let me know how much it would cost for the total website to get it going. thanks! I don't have a budget in mind yet, as I didn't know at all what this might take. So ignore the below posted budget stuff.