These are my tips for a family with young children.
We have a family of 5 soon to be 6 and small children generally want what they see and don't understand costs. My solution, since my hubby is a big pushover, is we compromise, I buy and bring things with us for the kids the glow sticks etc, and they get one larger purchase per child while we are there.
I also have a `DISNEY BIN` and In it when we come home from a trip I put away the mister bottles, the Disney hats, binocculars for animal kingdom, ponchos(which I buy at the dollar store) the expensive disney wands that light up and spin. (they do not realize they are gone and when they get pulled out the next year they think it is new, and they think we are the best parents ever( well we are but,

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I also bring their Disney plush animals and they stay in the room while we tour the parks. This way they know they have them and they are less tempted to want to buy every mickey and minnie they see! It is also neat to see the mousekeepers arrange them in funy positions at the end of the day.
I buy the Thermos Funtainers for the kids and put ice in them in the morning at the room and fill with bottled water that we buy at
walmart before we arrive. The Funtainers are amazing and they will keep cold for 12 hours so they say, my experience has been that they have kept ice for 18-22 hours. The kids always have a cold drink. This year instead of any other sippy cups I have bought and plan to use only these for water, milk, and juice the entire trip. This saves me money in the long run, we can buy drinks for the kids ahead of time and use throughout the park all day. We Drive and I hate finding a smelly cup that has slid under a seat and having to deal with it.
For our road trip down we get the I75 coupon hotel book and try to stay at one of them to save money.
I am sure I have more tips, as I am always looking for ways to make Disney more affordable for large families. We always take our own stroller and never rent, it saves a tonne over a vacation. We also travel during free dining which helps tremendously.