What`s the difference between promo and corporate discount coupons?

Hi guys.. I`m brazilian and I`m going to travel to USA in the next weeks.. I want to rent a car while I stay there, so I went looking for discount codes on the internet.. I found a good one, that seems to work on Thrifty, but it`s a Corporate discount code, and I don`t know if anyone can use it.. Can someone help?What`s the difference between promo and corporate discount coupons?
A promotion is just that, a promotional price which generally has an expiration date to use it. A corporate code is generally given to a specific company to use when they rent cars so the car rental company knows who uses it and what their arrangement is, what discount is offered.





I find that corporate codes aren't any cheaper than renting it without a coupon because they tend to price their cars UP so the discount looks like a deal when it's not.