Marketplace PHP Script Change As Per Instructions

I have the following script (please search functionality to get familiar with the script): [login to view URL] I have a landing page for the homepage so no change to that is required. I have also attached script so that you can view functions. I will attach a full brief of functions I need added/changed/removed to the winning bidder or you can request this if you like. Basically I need is to ensure that transactions will be between members. So if scott lists an item for sale and adam buys it, adam will pay scott directly through the website and it will instantly register a successful sale. The other thing I need is to make a change in the script where I can make the entire site a market place to sell 1 virtual product (virtual currency). So there will be no option to add other products, you can simply acquire more or less quantity of the 1 product, which is virtual currency. I will need the member area to show how much a member has (quantity) and they can choose how much of their balance they wish to sell to another member. The price will be determined by admin and members cannot change the price of the product. This will be changed at any time via admin panel and this change will instantly be reflected through the site including each members member area. On the homepage it will clearly display the price for the product at that time. Egopay will be the payment processor. members will require an egopay account and each transaction will be instantly between members egopay accounts. Besides the main functions listed above I will need a few simple customizations such as remove search form and replace it with facebook share button and replace category links with ad banners etc. This stuff will be very simple however it is also a part of the job. Please contact me if you have any further questions. Preference will be giving to low bids - please include examples of previous work. I am looking forward to hearing from you. Thanks.