The AK ones can be purchased at any counter service restaurant in AK. The adult one costs $10.99 + tax and is a very good deal. They give you a coupon with three tear-off sections, one for a popcorn or ice cream, one for a bottled drink (good for pop, water or powerade), one for a meal & drink at a counter service restaurant.
We usually purchase the voucher at the first counter service place we pass, so we can get something to drink early on.
I used my meal coupon for the peanut crusted chicken at Tusker house (7.99) and a coke (2.29) which would have been about $11 after tax. I used my drink coupon for a PowerAde ($2.50) and my ice cream coupon for a mickey bar ($2.50). Total value of the coupon ~ $16.