I am building a salon website for my friend & for every customer that gets a discount coupon from my website & gets a hairsalon service done, I get a % referral fee. How can I set this system up? I need to get paid before the customers take her service-right? The coupon code # system cannot work because, the customers can take the salon services with the coupon code from my site, but I wouldnt know if they got the service or not, unless my friend tells me. How can I know that the customer took the discount coupon from my website & in fact did take the service ?