The promo tickets have a limited use. Regular park tickets are good until the end of the year. Once 2013 prices are released this summer, those tickets will be good through the end of 2013. But, no you can't buy tickets now and us them in 2-3 years like WDW...well you can buy them, but you'll have to trade them in for current tickets when you actually use them and most likely have to pay the price difference.