Hi, Lisa! What a great question. I also find myself weighting out several different discount options when planning my family's Walt Disney World Resort vacations. I even find myself doing that when we aren't planning our next vacation!
My children are similar in ages to yours, they just turned 8 and 11 years old. We have had the Disney Dining Plan each and every time we visited whether it was free or if we paid for it. What I love about the Disney Dining Plan is that I do not have to worry about a meal budget or if I was going to run out of money before our week was up. I also like choosing entrees with my stomach instead of with my wallet. If you are like me, Lisa my eyeballs go straight to the prices the meals and then I make my selection between the least expensive items. Sometimes, I just want the steak!
For our trip we just took last month, we did not have the Disney Dining Plan for the first time. To budget for this, I viewed the online menus that are available. I selected the Quick-Service locations we normally visit and looked at the Table-Service restaurants we already had Advanced Dining Reservations for. I anticipated the meals my family would order and actually came out with an average we would spend at each meal. My estimates may not be the same as yours, as my boys eat a ton and both will normally chose adult entrees if I let them. I ended up over estimating a bit, as I had forgotten exactly how large the portions were. Since we were not using the Disney Dining Plan, we would share meals at times or some days we would eat a larger breakfast and snacked out way through the rest of the day.
I realize this isn't an exact food budget for you, but I encourage you to take a look and price some things out to see if your family would benefit from the free Disney Dining Plan being offered.
Have a magical day, Lisa!
~Rachel