A Web Scrapping form fill out change pricing every 5 minutes software

I need a software to change prices for me every 5 minutes or a choice of time of my own. I want it to read what is the lowest price and change my price to 1 cent less and submit. I want it to cycle unlimited amount of times. I want to control how fast the program changes and saves the form i want the software to have an option for me to setup minimum price and if the minimum price is met, the software will setup the price as $99. Example: Lowest price is 47.99, submit the form on my site for $99. but if I turn it off, it will submit the form price as 47.98. *I don't want you to use a slow mouse moving software that will take too long, it must do a whole cylcle in 5 minutes.