I cant help you on everything, the 01 E came with included service while under warranty, flushes, wipers, oil and filters. your warrnty ran out at 4/50 did you abuse it since then?
Roadside assistance comes to your location and will replace a battery for $135no labor, in the the shop they do.
A brake job should cost no more than $500 rear rotors, pads, sensors and brake shoes, less for the front (no shoes), including a flush.
I would check with a good indy and another dealer. I have always been treated fairly by my (service advisor) MB dealer, he left and the dealership changed hands.
Took my car in for a window regulator, and they came up with a list of everything they said needed to be done, plugs caps and rotors (they did 10,000) ago, brake flush (they did 2yrs ago), AC filter (they did when they did evaporator) air filters and wiper blades (I did recently). I could go on and on, I took my complaint to the service advisor and was told "we go by the recommended items shedule"
They finally agreed to only suggest things that they can visually see bad, I bet a lot of uninformed people have been fleeced. As you know mechanics are paid by the job (everything has a hour value) the more they can run up the hours the more they make. If they are quick they can run up more than ten hours in less than eight! The hourly rate to the dealer is just under $100