We are a family of 3, and we budget like this:
Tips - go on to All Ears and you can find out the average cost of the meals and you can budget your tips. Also, we budget for Mousekeeping.
Other - we plan and budget for (1) ride photo, (3) refillable mugs, etc
Other plans - This year we are planning and have budgetted for Characters in Flight, My Mini Cake Surprise, Pirates League Makeover for DD, etc
Daily Budget - After all that is accounted for, we then have $50/day for extras. Last year, we did not spend this much, but it was nice to have and know we had enough.
We only bring cash and travellers cheques and do not use credit cards, that way we do not go over budget while we are there.