I'm not sure what all it covers, but for us it was $60 per adult and the kids were free.
We booked separate travel insurance through Travel Guard (booked through insuremytrip.com) and got all the coverage we needed (and I'm sure as much as AAA offers) for $60 total for our family.
Keep in mind, when booking separate insurance, you only should cover the non-refundable portion of the trip costs. That should be your airfare and any deposit you cannot get back from Disney (probably $200), etc. You do not, and should not, insure the total cost of your trip, on that portion you cannot get back if you have to cancel.
I agree. Read the fine print on your deal with Disney.
I fly SWA, so while they won't refund your money, they will give you a voucher for the canceled air - so for me, that's basically a refund, since I fly SWA several times a year.