I have a simple PHP script. I would like the user to have to provide a 'credit key' e.g: '1931089AMXIAJIOJX' in order to use it. Each credit key will need to be able to be used a certain number of times (e.g 100 times) before it expires and is no longer valid
Preferably there will be functionality to check credit of each key for the user.
To see example of something I would like to achieve, pretty much exactly the same as this; [url removed, login to view]