buying Auction portal website php scripts

Auction website scripts I am looking for a auction website scripts like ebay. It must have a very important function as for seller to sell digital product. During listing, the seller can preset the download link, so when buyer paid at buy it now, it will receive the download link information to download the digital product. The listing also can be found by search engine, just like ebay. Support bidding, fixed price, can open store, store inventory, classified ads, etc Must have feed back rating also. Payment provided using Paypal, if additional also accepted. So, this auction site is meant for selling digital product. Please give me demo site is better. I am willing to buy the php scripts.