You just look at pics and pick condos that have Disney theming... most of them do- again, we use Florida sun vacation homes... you can see what is available and their prices on their website.
And PS. You still have to shell out money in the dining plan. The plan does not include tip, or alcohol- and if you stay in a value resort, only comes with quick service plan.
We can stay for two weeks offsite, paying out of pocket for food (going to most character breakfasts and sit down dinners almost every night) for the same price as one week onsite with free dining.... Free dining doesn't even touch the savings from staying offsite.