I got a dynamat extreme bulk pack from Amazon which is 36 sq ft. It covered inner and outer door skin for the front doors, the area directly behind the rear door speakers, and the rear quarter pannels and liftgate. There are dynamat alternatives, but I would say you will want about 36 sq ft of whatever brand you get.
For the record, I recently used Raamaudio's RAAMmat BXTII, and I am very impressed. The price right now makes sense, and it is a true butyl product that even Harmon Int'l signed up to purchase from Raamaudio. BXTII is what you want, NEVER BXT standard.
Don't forget your closed-cell foam over the deadener.