We go to the theme parks more than 5 or 6 times a year both in Florida and in California. Both my kids are 5 and 7 years old. One essential thing that I do to save money is to get the kids small fanny packs that they keep around their waiste. Get the better quality fanny pack that holds the bottle on the outside. Find out what they like before you leave home so you can pack the right stuff.
Pack them full of the kind of treats that they really love at home.
fruit roll ups
gummy bears.
dried fruit and nuts
Peanuts
(chocolate melts) but M&Ms are a best bet.
Bora Bora are those organic wellness bars at costco that have nuts and fruit in them.
Doritos are a big hit but you can't get cool ranch flavor in the park. Pack the specialty small one serving size in the suit case.
I like the one serving size Cheese It's but you can't find those in the parks.
Splurge on what they like because if they don't eat it,they will be carying it around all day long. Check their bags when you return and see what is left. Don't forget to restock the fanny packs when you get back to the hotel room for the next day with a fresh water bottle and Crystal Light 1 serving packets.
Get the small child size bottle of waters that have the reclosable sport tops on them and 2 or 3 crystal Light 1 serving packets. The kids LOVE this stuff. You can refill the water bottle with drinking fountains around the park and then sprinkle the crystal light in the water. I know this sounds like just Cool Aid but this stuff tastes great! It will keep them hydrated all day long and save you $$$ dollars. Plus you will be recycling that plastic bottle too (how environmentally friendly is that?)
Encourage (dare I say train?) your kids to spend the $$$ on something they can keep, not on expensive overprised candy, Ice Cream and soda in the parks.
All that said, I often have to splurge and get one of those toll house cookie Ice cream bars in the park. They are my favorite.