If you plan to go to other places in Europe, figure on extra costs there. But this is because we are trying to economize most of the time and are willing to eat fast food meals. If you want to eat table service meals most of the time, then you should probably double the estimate. You will also need to factor in exchange rates, which may also add to costs. Hotel packages may include park admission, so consider this in your pricing.
Souvenirs can really add up.
I do think it is a good idea to budget for souvenirs so that you have an idea of what you are going to allow yourself to spend. When selecting purchases, keep in mind that most of these items can be purchased at the local Disney store, so try and get things that are unique to your trip. While these costs are in dollars and based on average exchange rates, keep in mind that a drop in the value of the dollar can cause these prices to rise.