The first step is to "accept the things you cannot change", like the simple fact that everything in Disney is expensive. We went the day after Christmas as a day trip (in FL visiting family) and the tickets alone are going to cost you just under $400. If you can go through AAA, do it!
As for food, go with the meal plan. We did it and it worked out well. There were a lot of options and with small children we had no intention of eating in the "fine dining" restaurants!
I would strongly suggest that you look into their "trip packages". The reason I would suggest this is simple- getting in-and-out of the park is a pain, but if you are there for multiple days and have a room with a kitchenette you can eat breakfast and lunch in your suite and have dinner in the park. Because you aren't "commuting" to-and-from a hotel, you wil save the daily parking fee and can take the park transportation anywhere you want to go. You can also go back to your room for naps and then hit the parks again when you are refreshed. You also wouldn't need to rent a car.
As kids (grew up in FL), we would go to Disney for 3 days each summer because that's when there are the fewest crowds. We always stayed at one of the "lesser hotels" in Disney and maximized their "free amenities".
Remember that in the "cooler months" it can take you an hour to get into the compound, park the car and actually get into the parks- if not more because of the crowds.
Start a little "Disney fund" for each of your children. Drop a quarter in there each time they help around the house, do something nice for one another, etc. When it's time to go, count it up and there's their souvenier money! We did this with my son starting in July... by December he had enough in his little bank for a stuffed animal and a bubble gun!