Hi, Kimberly!
One of the many things I love about a Walt Disney World Resort vacation is once I am there, the impact to my wallet is extremely minimal. After paying for your hotel, Theme Park tickets, and meal plan - there is little need to spend much more!
You will want to bring gratuities for Bell Services, Mousekeeping, and your servers if you dine at any Table-Service restaurants. Another expense you may encounter is if you wish to purchase any snacks or drinks you may not want to use your Disney Dining Plan credits for, such as alcoholic beverages or inexpensive snacks that may not be a good use of your snack credits.
Don't forget the souvenirs! As you can imagine, you could spend as much as you would like on gadgets, gizmos, who's-its and what's-its! When budgeting for souvenirs, I purchase Disney Gift Cards from my local Disney Store and Target for each of my children. This limits them to only spend the set amount on their gift cards. They know when the money on the cards runs out - they are done shopping. The remaining gift card balance prints out on the receipt after they make a purchase, so they can easily track how much they have left. They tend to make wiser purchasing decisions when they realize they are spending their own money.
After you have returned home, you may wish to purchase photos taken by Disney PhotoPass photographers. For extra savings, Memory Maker is a budget friendly way to download and every photo without having to decide on only a few. Purchase Memory Maker at least three days before your arrival for an advance discount.
Have a magical day, Kimberly!
~Rachel