The not expiring part is the problem- they have lots of good deals on 3 day tickets, but they all expire right away. We bought a 2 day, get one free from AAA last year that was a good deal, but they were only good for a week after you started using them.
There is also a Universal board on here- maybe they can help?
try www.centralfloridatravel.com - they have discounts for all tickets including universal and the 3 day tickets I bought did not have expriation dates - always ask when you purchase though.