The best way to find out would be to go to your local AAA office and get quotes; compare what you would save with an AAA membership and decide if it is worth it to you. I may be a bit biased, but your membership can pay for itself in other ways if you chose not to book your Disney trip with AAA. Only the person making the reservation needs to be a member, so if you can save $120 on your trip by spending $50 (that's the price of a Basic membership at my club in PA) than I would say it well worth it! PLUS you can Show Your Card & Save at TONS of places while on your trip and at home!
The amount of certain packages is limited and AAA only has a certain number of rooms to book with your membership discount, after that you would pay rack rate. You can book your entire package (Dining Plan, room, tix, and airfare) OR you can just buy tickets but they are not MYW tickets- they are the Park Hoppers and Park Hopper Pluses- and on average you can save about $15-18 a ticket (and these don't expire!). You can also pick up discount tickets to Sea World and Busch Gardens Tampa.
I think I am going to go see a man about a Disney vacation now...
Hope this helps, let me know if there is anything else I can do for you!