Database ad-driven webdesign project

Our client requires a database in which adverts can be stored. The ad ranking is a bit more complicated in that there is only going to be one ad on the page at one time. The selling point is that no matter what the companies pay they will still get a good sized ad in a good position. What they are paying for is ad frequency, for example if there are 10 "plots" on the site and each plot is a pound - if you spend a fiver then your ad will have a 5/10 ratio, so your ad will load for every 2nd visitor. As opposed to someone who only spent a pound, 1 in 10 visitors would see there ad. The plan is to have 1,000,000 "plots" at a dollar per plot. (the theory is similar to [login to view URL] - the difference is if you spend a little you still get a visible ad) I would also be looking to have some fixed ads or services and a search engine may be useful if it will be able to filter through the ad database - i.e. Dan from Dan's shoes only has £20 to spend on advertising and is wondering whether it's worth doing it on my site. The search engine would be a sale closer in that Dan's Shoes ad will come up if someone searches "shoes". Finally I want a time limit on the ads so that each time a new ad is loaded it's another "hit" which makes for more impressive stats. Either that or a refresh button that just refreshes the ad on each click - giving some novelty factor for guests in letting fate decide which ad to see. We need an ecommerce function which uses payapl to invite people to purchase as much of a slot as they require. We also need to have it so when the purchase is completed, the new ad is incorporated into the design. ## Deliverables 1. Fully functional website. 2. As many alterations as we require at the design stage. ## Platform 1. Any that you find appropriate.