We got a DC card through a corporate program for $29....we were going to save about $40-$50 buying Park Hoppers. The real savings however ended up being with a car rental. I had a weekly minivan rate of $209 with Dollar (using a code from the Budget Board). Shortly before our trip (a few weeks ago), I checked the National site to check rates because that's my company's preferred supplier and I have an Emerald Aisle card. The Corporate Rate was $219/week. I then put in the National DC code...the DC coupon indicated it'd be 10% off, and I assumed 10% off the list rate, but what they ended up giving us was rate of $219/week matching the corporate rate and then a $61 discount on top of that! Net, I got a 200% return on my DC card before I even bought any tickets. Just wanted to mention this because I originally ignored comments about rental car discounts figuring that all the discounts/corporate programs are about the same, but the DC discount really does amount to something.