Plugin for shopping cart platform

I'm looking for someone who will write for me a simple Plugin for one of the e-commerce(shopping cart software) platform. The goal: 1. Currently, I'm unable to display to my customers how many percentages of discount they gain on a particular product. Customers can see only the original price of the product and price after a discount. The Plugin will require a simple piece of JS to calculate the difference betwine original product price and price after a discount. The result from calculation should be displayed as percentages on the product page and product lists. 2. The Plugin will have to display on product page information about the shipping methods available in the store, so the buyer will know what are the shipping methods available in the store and what is the cost of each of them without visiting store basket. 3. The Plugin should have configuration page so the store owner will be able to switch on/off features from points 1 and 2. The Plugin should allow store owners for same basic adjustment of fonts colors, a position of a badge (with percentage discount) on the product picture. * More details about the project available on request * I provide the hosting / domain / SSL / Plugin wireframes