First your car is worth what 5-6K? Most of this is preventive maintenance. I wouldn't spend 3K PMing a 6K car. I wouldn't replace control arms unless there was a real problem with them. Get a second opinion on that.

I did a complete brake job on my wife's car with new rotors and pads for $100 and a couple hours time. A brake job shouldn't cost $1800 and your rear brakes were probably fine. I would be really pissed if they wanted to charge me for a brake system flush 4000 miles after they charged me $1300 for a brake job. The "just give me back my damn keys" kinda pissed.

Unless you have zero access to water hosehose don't pay them to flush just drain it and run a hose through when it is hot and running then add new coolant. Look it up on youtube if you don't know how.

Don't mess power steeringeering system that isn't messing with you.

Discount tires will rotate your tires for free.

Unless your drive belt is cracking or splitting leave it alone. The new belts are much beter than the old ones. I have two vechiles with 200K miles on them and teh belts are fine. Just check it now and then when you are checking your oil. Yes your car as 100K miles on it you need to check your oil.

Buy a wire brush and knock the corrosion off your battery yourself.

Edit: Just noticed the $60 for cleanng the terminals. That is about what a new battery would cost you.