We do budget trips frequently - we spend less and go more often. We typically spend between $2000 and $2600 for a trip for our family of 4. Here's how:
1)
We stay at Value resorts with a good promo - like Free DiningOR
2) We stay offsite and use non-expiring tickets we bought a few years ago (works out to be about $26 per day per person for the parks with these) to go to the parks 3 - 4 days.
3) No BBB for our DD...If she wants to be 'fancy' for a meal - I'll do it at the room (her nails, her hair, the dress) - but we don't really even do that often - especially in the summer heat - she ends up in a spray water jet (or on Splash or Kali) so soon after that all the work is messed up anyway.
4) If we don't have Free Dining -
we bring a bunch of food and bring at least one meal, plus lots of drinks and snacks - to the park with us.
5)
We don't rent a stroller - since the price increases, it saves a ton.
6) As far as 'spending' money for the kids - I buy them 1 - 2 things before we go at Big Lots. Usually some sort of Disney toy and matching t-shirts. I give them the first toy on the plane ride down. And give them the t-shirt on the morning of the first day at the parks. This way - they already have two 'new' things and don't need any/many down there. We usually let them buy 1 - 2 pins (we don't get into the trading either but I have found that the pins themselves are great souvies because you can get one for $8 or so) at the parks, then we go to DTD and let them choose one thing each (reasonable - in the $20 - $30 range) for their one 'big' thing for the trip.
7) With Free Dining - we buy VERY little OOP. With good planning you don't have to. We bring a box of cereal and some mini-bagels in the suitcase with us. Use snack credits to buy a couple extra things and use those for breakfast. Then we share some CS credits to make them stretch a little farther.
8)
We get base tickets. No need for hopping for us.
9)
We use Magical Express when staying onsite and do not rent a car. We like WDW transportation.
I think that hits the major areas where we save $$.