Welcome to the Dis!
If you are staying off property, then the meal plans are not available for you to purchase. Yet, since you will have a car, you will have easy access to some great local restaurants and grocery stores.
Here are a few things to help you plan your vacation:
Purchase your tickets from an official Disney distributor, but not from Disney itself. I recommend
Undercover Tourist. They are an honest company with great customer service. Cannot Say Enough Good Things about them.
http://www.undercovertourist.com/
As to food, that is a very personal and subjective question. Do you really like having sit down meals at fancy restaurants, are you a grazer who likes several small meals a day, or are you an unabashed "junk food" fan? Your answer to these questions will shape how I respond, but I will say that if you eat breakfast at your condo, and then do lunch in the parks, you do NOT have to spend an arm and a leg.
Here is a web site that lists all the current menus and prices.
http://allears.net/menu/menus.htm It is a lot to dig though, but for example, at Epcot there is a great kisok outside China, The Joy of Tea, that offers Lucky Combo - combination of Pork Bun, Chicken Pocket, an Egg Roll, with your choice of a soft drink and an ice cream $9.98
You can have a nice meal for ten dollars, if you plan well.
Parking at Disney is expensive, fifteen dollars a day, so you will need to budget for that, but once you pay, that is it for the day, so if you want to go to another park on one day, just show your receipt, and you will not have to pay twice.
One of my favorite Disney trips happened in the late 80's. I was in school, and poor, but I wanted away from the misery of an Indiana winter. So, when Spring Break came around, my two brothers and I, with my cousin Jen, piled into a tiny sports car with an almost non-existent back seat and drove all day and night to Florida. We brought a small tent and stayed at the KOA campground in Kissimmee. My luggage for the entire week was a small backpack. We ate peanut butter and honey sandwiches, ate a huge bag of oranges, and drank water. We only had enough money for one day's entrance, and so we did Epcot one day from rope drop to when the cleaning crew swept us toward the exit.
The only thing I bought in Disney was a Mickey Ice Cream Bar.
It was a fantastic trip. My brothers and I still laugh about how happy we were around the square concrete swimming pool at the KOA. Yet, we were warm and the sun was shining. Life didn't get much better than that.
I share this story simply to say that there are many ways to enjoy a Disney Vacation, and not all of them involve staying on property.
Have a magical vacation and enjoy planning your trip.
