Wow, you've got quite a variety of responses...
Mine is different, so I'll share.
My ten-year old daughter and I will be going for 6 full days and two half days in February. The only way we can do such a long trip is to budget carefully, so we're staying at the Desert Inn & Suites @ $69/night.
We'll be having breakfast and lunch in our room (I've always done it this way.) and will have dinner in the parks. We'll generally share food (ex. pasta and salad at Redd Rockett'--looked at the menu, and the prices seem awfully close to what I shared with friends a dozen years ago!) We'll also bring in healthy snacks but splurge a bit on yummy treats to share also. I'd originally planned on $30/day for this, but decided to go to $35 to allow for a bit more flexibility.
I'm budgeting with Gift Cards. It's a bit of a risk, since I've got 8 $35 gift cards plus others (listed below). Will be a big loss if we lose them, but it's a much bigger risk for me to allow myself to bring in a debit or credit card into the parks...
For spending money, I've budgeted $100 for hoodies, since we both want one and they seem to be about $60 for adults and $40 for kids. I've then allowed myself $100 for the entire trip for spending. Hopefully that's too much and I can save it for another time, but I have a hard time resisting the cuteness. My daughter is much more practical and will sometimes talk me down from buying things we don't need

Not sure how much she'll have. Depends on if she gets gift cards for Christmas. I'm thinking about $50 will do it for her.
She also wants to do a Character Breakfast, so she's asked for a $50 card from either her Grandma or Grandpa. She knows they might have other gift ideas, so we'll go if we have the money. And I know she wants to do Studio Disney 365, so I've gotten her a gift card for second level cost of that. Anything more there and she'll take it out of her own gift card.
Have fun!!