Discount based on Code during checkout
Hi All,
I am looking at creating a 10% discount on the order total if a customer enters a special phone number (code).
The phone number would be in a table and could be one of many in the table, but as long as the phone number exists, then they get the discount.
This will be part of a very basic referral / affiliate program we are trying to create.
The question: Is there something in Zen that I can modify to do this? May be a contrib that would get me going in the right direction?
Appreciate any help / suggestions! 
Thanks
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