Hi Kyla,
Welcome to the Disney Parks Moms Panel! How exciting to plan a trip for your 3-year old daughter!
If you already have a vacation package that includes theme park tickets and a
dining plan, then your spending should be minimal. On our first trip with the girls when they were 5-years old, we spent seven days and did not buy one souvenir. The girls did not ask for anything! Prior to the trip, we had gone to a Disney store near us to buy their princess dresses and other trinkets. We brought our own snacks with us to have for breakfast. On that trip, we had the Disney Dining Plan, so we had one quick-service and one table-service meal plus two snacks per night of stay for each person on the dining plan. With our own snacks as a supplement, we did not purchase any additional food.
If your dining plan includes table-service meals, you do need to budget for gratuities. We typically tip 18% or 20%. for each table-service meal. If you have a six-night stay on the Disney Dining Plan, then each of you will receive six table-service meals. On our last trip, tips for our family of four were usually between $27 and $38 for each table-service meal. To make sure that you do not run out of meal or snack entitlements, I suggest that you chart out your meals. I do a daily schedule for the trip and then indicate how many entitlements we will use at each meal and how many snacks we will get each day.
Now that our girls are older, they earn their own money for souvenirs. On this past trip, they spent about $100 each - they each bought a new pair of Minnie Mouse ears and a giant stuffed animal that they had to pay to ship home.
Kyla, enjoy this time with your 3-year old. She may not ask for much. Although there is no average spending amount I would suggest, I hope this information offers some guidance!
Magic, memories and Minnie Mouse hugs,
Donyell