Script that increase sales price on salespage

I am looking for a script to use on my salespage. This script will increase the sales price at a given time interval. For example, for a 10 day interval the price starts at $20 and increase by a tiny amount for those 10 days until it ends at $50. I would also like it to auto-restart for 10 days. The 10 days is just an example. I want to be able to control the time interval. For an example of what I want go to: <[login to view URL]> This is exactly what I want. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform Just need it to run on my website.