AJAX live data from database with counter for auction site

I need a simple script for an auction website. I need live data to be shown (using ajax) which will update the current price of an item as and when people place bids (preferably) or every 1 second without reloading the whole page. It also adds 15 seconds to the clock which is also live and counting down continuously. I am trying to achieve something similar to this [login to view URL] I understand this is quite a simple thing to achieve but i have no ajax experience. I have done no ground work on this so you would need create the bid button, price indicator, timer indicator, the mysql table and php file.