I have every product in a store marked down by 50%. If a user checks out with the 50% discount, they are added to our discount club (there is wording on the checkout page that states this). I have a checkbox that a user would have to check to be excluded from the club, but if they check it they should not get the 50% off. Is there a way to do this?

I imagine it must be controlled somewhere, because the original price is shown next to the discounted price...

I am familiar with PHP, so I can code the "if POST['checkbox']" code myself, I just need to know where this is handled.

Thanks.