I have been traveling to WDW for 10 years. I have always do my research to find the best deal. There are a lot of websites to help in booking a trip. But which is best? Well here is how I book a trip. In the beginning I use a Travel Agent that does Disney trips. These people go and do all the work to making your trip easy. They can do a payment plan.
Travel Sites where you can book packages of Hotel and Flight. I don't use these site because they don't have Southwest flights.
I have checked Southwest Vacations to get a price for a trip. They do have sales on Disney Vacations. They are deals good also if you want to stay at A of A and you want a Little Mermaid room. You can get the Disney discount. Disney website doesn't have a discount on theses room.
The way I book my trip is book it separate. Air though Southwest and Room though Disney. Since I have AP I don't get the packages.
I book Room Only and I get the AP discount. I can save $100 on my stay.
I book my flight at least 5-6 months a headed of time. You can get better deal the early you book. My flight are under $400 round trip. Also booking on Tuesdays you can the best fare.
I book my room though Disney. If I find a better deal I can re-book and I can lower my deal.
Finding the best deal you have to do your research.