The amount of money you need to spend in Disney land will largely depend on the expenses you are actually going to incur. To enjoy your vocational trip without having to break your budget, you ought to plan very carefully and make use of the available tips to save some money on your visit. Check out http://gocalifornia.about.com/cs/disneyland/a/gencost.htm for more information.
I went two years ago - and dang, were the prices high!!! For example, they had charms that you could make bracelets out of down there - and they were $2.00 apiece! For a tiny charm. What's more, if you want to get anything worthwhile, I'd recommend you'd bring at least $500.00 extra at the least. (Depending on how long you go - around 100.00 - 150.00 daily)