php/mysql developer to write simple coupon voucher code - repost

I need a php/mysql developer to put together a simple coupon voucher script. What I need it to do is take an email optin form(I already have one from [login to view URL] ) and redirect it to a URL after email submission that will generate a random coupon code and stamp it on an image of my choosing which I assume would need to be stored in a folder on my server for the script to grab and stamp the random code onto. I would also like it to store the random code and have a login area so that once the code is brought into the store to be redeemed, the merchant can login and cancel out the coupon code so that it can't be printed numerous times and used over and over again.