Build a Website Script

I need a custom website script for my website. It's basically a bartering website for the U.S. only but will expand in the near future. We will only pay in percentages but this can be negotiated. Also, the site currently makes $30 a month and it expands all the time. If you have any doubt in your mind that this can't be made, please do not bid. Those who do not have access to PayPal, do not bid. Thanks, Owen