Here is a site which offers you a 50% off deal on your first order from dominos
[Only registered and activated users can see links. ]
simply put in a new email each time you want 50% off (Email doesn't have to be valid as code is displayed on screen)
If you use the same email again and login you will also get a different code for some sort of deal. It wont be 50% off unless you use a fake email each time. Code is for minimum £25 spend.
Enjoy and good health