Online price optimization tool for shop

The main target of this project is to build a stand-alone price-optimization online-tool for a dedicated online shop with about 20.000 articles. The users of this tool will be non-technical persons (the owners of the shops) who want to find the optimal price for the articles in their shop. To find the best price, the user wants to compare their current shop prices with prices of other shops. These comparision-prices have to be read from web services or similar sources. Due to the big amount of articles, the tool must be able to sort, filter and show all these information in well aranged tables with several AJAX-based comfort-features. The user should be able to change the prices of their articles in a product-by-product way or by bulk rules depending on various criteria. The system should be able to repeat these changes automatically each day. The user should be able to create and manage rules for automatic prices changes for different groups of products. All changes that take effect in the shop should be mailed to all users. It is very important that the front end of the tool is fast and easy to handle. AJAX will be important to use. The visual design of the tool is not really important. There is no need for high-end design. The technical interfaces to read from and write to the shop will be quite flat database tables and two PHP-functions which will be provided to you by me. The tool should be able to handle different users (with username and password). But all users have the same privileges. All changes to the prices of the shop must be logged by the tool. The user should be able to see the history of all prices - including the comparision-prices. The project will start as soon as possible - for the next two or three weeks your availibilty should be at least 6 hours per business day for working on this project. I need a written invoice on plain paper from you after the project is paid. This invoice MUST be mailed to me by normal mail (NOT by email). This is needed due to the german tax regulations. All payments will be made through freelancer.com. !!! You will find much more details for this project in the WORD-Document that I attached. Please read this in full and carefully before you bid or ask me any questions. !!!