App to Send Estimates

need an App that will extract price and shipping cost from Ebay or Amazon, bring total to convert to by a formula which will evaluate and assign percentage according to price level, the app needs to give an estimate to customer. the customer will decide if he sends an approval to the price or saves it for later. to be clear the formula needs to select the percentage to charge over the price... from a chart of options example: if the price is $5 the price window results should show $10 (at %200) If the price is $150 the price window results should show $217.5 (at %145) the percentage chart options need to have about 6 fields to fill according to needs.