You can lose a ton of money in dining at Walt Disney World, especially when you're tired from a long day at the parks, don't have an advanced dining reservation, and don't feel like going anywhere. That never happens on a Disney vacation, right? 
Most people break down and order room service out of nothing more than pure exhaustion. I've been there and done that, but it's usually when I'm on a Disney Cruise ship. Out at sea, the options for food are quite limited and room service on the cruise is free, except for the tip.
At Disney, you have other options. Believe it or not, you can order a pizza (or any other take-out food) from off Disney property and have it delivered. Most people don't believe me when I tell them this little fact, so I took a picture of a Papa John's delivery guy bringing a pizza to the Polynesian.
Instead of ordering room service, order from a local take-out/delivery restaurant and you could easily save as much as $50 on a single meal for your family! If you're staying a week at Disney and order a single room service meal just 3 nights of your vacation, you just saved yourself $150 -- probably just about enough to pay for one of your flights to Disney.