Pull results from existing data

Please excuse me if i have miscategorized this.

I get data on Amazon.com pricing. This pricing data will have 6 prices, 3 are the cheapest prices for the item in new condition, and 3 are for the cheapest in used condition. the data is from a third party provider and i am unsure of the format, but the information is collected from Amazon.com

I am looking for someone who can write a script or program that will go through this data and display any products where the price variation between the 1st and 2nd cheapest item is x.

I would like any person/people interested to contact me with any information they need and pricing, as well as details of work they have done.