Create web based software tool.

We are looking to develop a software where it is able to workout retail price for us based on different variations, i.e. Ebay, Amazon, Direct Sale and Price through Website. Variation will be based on Postage Cost Amazon/Papal charges Final Value fee etc. And also prices in different currency UK, Europe and USA I am trying to get a software tool which will enable me to add all the inventory in there which I have and workout retail price for me based on percentage taking all the costs away. Currently I use spreadsheet which I will send you, so in there in selling Gross column if you put any price that will tell you will change the percentage and VAT and that I will keep changing the price until I get the correct percentage I want to sell that product at. What I need from the tool 1 – To provide us with Retail Price based on % on the profit for all the different Platforms as advised. 2 – Be able to handle our entire inventory around 2000 SKU and we are still adding more. 3 – Be User friendly easy to manage. 4 – We should be able to change the Cost prices manually in future if needed. 5 – Be able to update the prices for current SKU once new price list has been uploaded, and also be able to add in New lines and highlight in some way to make us aware new products have been added into inventory. 6 – We should be able to upload the inventory on regular bases via excel, CSV. 7 – We should be able to set various filters where we can refine our search i.e. By Brand name, Category. 8 – Be able to search inventory via SKU or title etc. 9 – Should have some sort of function were we are able to mark the SKU to suggest if this item has been listed in particular Platform. 10 – Once new pricelist is added system should be able to let us know if the prices have changed i.e. difference in Red to suggest price gone up and Green to suggest price gone down and what was difference in price from last upload. 11 – Has to be able to accommodate for Euro according to Exchange rate which we can enter manually if needed. 12 – We should be able to download the products in sku and retail price in csv or excel format 13 – We are going to need to be able to associate each products with different type of mailing list – I.e. Standard letter , Large letter, Packet, And same of euro PS apply your proposal if you can start immediately