Hi Abbie and welcome to the Disney Parks Moms Panel.
Questions like this are notoriously difficult to answer as every family's eating and spending habits are different.
In order to work out roughly how much spending money you will need, here is what I would recommend:-
1/ Consider how many and what sort of meals you are going to be eating each day. Will you be
dining solely at Quick-Service dining locations within the Walt Disney World Resort? Will you be making Advanced Dining Reservations for any Table-Service meals during your stay? How many snacks and drinks do you expect to be having each day? Will you be purchasing any food or drink from a local supermarket etc to take to the Disney Parks with you each day?
2/ Take a look at the menu section of the unofficial website www.Allears.net to get an idea of how much food and drink costs at the many Table-Service & Quick-Service dining locations. (Remember that you will also need to allow for gratuities at any Table-Service meals.)
3/ If you won't have a rental car during your stay to visit a supermarket, consider ordering some groceries ahead of time to be delivered to your Disney Resort hotel from a company such as www.gardengrocer.com. Taking some of your own drinks and snacks to the Disney Parks with you each day can really help to reduce your spending.
4/ Decide how much money you will be allotting for purchasing souvenirs. Perhaps set a budget/limit for each of the boys and yourselves.
I hope that this has given you some pointers and helps you to make a judgement about how much spending money you will need during your 2-week stay.
Wishing you a magical holiday filled with memories which will last a lifetime!
Emma