Excel Spreadsheet custom programming

I require an Excel spreadsheet programmed so that I can open the template and scan in barcodes, The template must enter each item barcode in column a exactly as the barcode reader sends it (number format or perhaps text), Column B must then acknowledge the scan as qty -1........I require the items to consolidate each like item and add the qty together, For example if I am to scan two like items with barcode 123456789123 then the result should be the line reading 123456789123 with a qty -2....the format must be CSV in order to be imported into my POS software. I would like the current item to always be at the top of the list and the cursor should sit in the qty box for that item. I would like to be able to enter an item manually as well, for example if a barcode was not scannable I could then punch that number into the very top cell and when I press enter the cursor should then go to the qty cell for entry there. When the file is saved it should ignore the top line or manual entry box that you create, The file needs to save as a CSV file very easily. Basic operational layout: 1- Employee opens the template from the server. 2- Employee can either scan the items or manually enter them into the manual entry box provided. 3- The scanned items add up as negative qty (eg -1, -2 etc) they must consolidate like items and add up (for example if item#1234 is already in the sheet as qty -1 and another one is scanned the outcome on one line should be #1234 -2 and the same should happen if items are manually entered.........I would like to be able to just enter the qty into a cell and have the system add the - in the front of the number (for example I scan #1234, the cusor then moves to the qty cell automatically and the default action is to add -1, If I have 10 of that item I could enter 10 into that cell and the outcome would be -10. 4- The spreadsheet is saved via "save as" as CSV, the save should automatically ignore the manual entry box that you create or the blank line at the top of the list that is left open for manual entry however you choose to make the manual entry work. I would like this sheet to work very well with a very good layout and operation and am willing to pay a bit more to get what I want, Please be sure when bidding on this project that you are going to provide me with a very very easy to use system with a great layout and preferably a separate text box for manually entering items that will not scan. There will be ongoing projects as a spin off on this project and I am looking for someone reasonably priced that can get my projects done in a timely manner with professional results. I look forward to working with you and thanks for bidding Sincerely, Jason