Coupon code for checkout (24 Hour Turn Around)

We need to get a coupon code functionality finished ASAP. EG: Either send a specific code to a user so it only works for them (like a discount code, via email), or have system like codes that people can hand out to each-other (like a coupon code). We had a developer start the process, and it looks to be close to completion, but we need it done ASAP (24 hour turn around) Please see [login to view URL] for what you will be working with. Thanks!