Auto pay software based on the price and availability on the eBay's API

I need a PHP or ASP.NET application which will be able to get a single or multiple ASIN numbers in an excel or CSV file at the same time with billing address information to pay it automatically, you should notice before purchasing we need to check two conditions such as it's price and availability. *Conditions: If the price for either of the items is less than (%15 cheaper) with the value of provided excel (work as a database) and also the product is still available on the Amazon, whole of the items will be paid for it with the given billing address information, otherwise, the process will be stopped, therefore, the output will return what eBay might give you as a string or whatever else. The script should give the values with a query string like the given example: [login to view URL] 1-2-3&BillingAddress=D&Name=E&LastName=F&Pay=true