Hi Bridgette,
Welcome to planDisney, and thanks for stopping by with your question!
One of my favorite things about taking a child under three to Walt Disney World is, you guessed it, it doesn't cost anything! People may try to tell you they will be too young to remember the trip, and that may be true, but as a parent you'll remember every magical moment.
Even though you won't have to pay for a separate meal, because your child can share off of your plate, or can eat at restaurants where food is served family style or ones that have buffets, you'll still want to include her in the dining reservation. That way you'll be seated at a table where there is enough space to accommodate your whole party, and you'll be able to request a high chair.
I hope you are able to enjoy some fun character meals with your little one.
Hollywood & Vine in Hollywood Studios and
Tusker House in Animal Kingdom are two that you may enjoy.
Hope this helps. Have a magical vacation!
Diane