I worked on my cars in gravel driveways and the side of the street for 20 years, only recently got a garage. theres a lot of gold bricking in that estimate, they shouldn't charge for swapping out the strut and then charge more labor to swap the boot, they've already got the thing apart on the bench...

Okay definitely sounds like there is a brake problem, could be the master cylinder yes. Could the clear li=quid be brake fluid - did you check the level of that reservoir too? Maybe there is a leak at the MC.