Brakes creaking at a complete stop

I have a 2007 prius with just over 70,000 miles, and have begun seeing a few nagging small issues here any there. This car has not had any service done to the brakes as of yet.
Recently, I've been noticing a creaking or clicking sound when I'm at a full stop. The creak or click happens as I depress the brake pedal further or release the brake pedal slightly (while still at a stop). The sound is like a beer can being slowly crumpled but with a higher pitch.

With the age of this car, there is noise when turning and braking which other threads have pointed out. That noise seems unrelated to this ticking/clicking/creaking as this noise is indepedent of any movement in the car.

Any insight is much appreciated.

 

Thanks @bisco, was hoping for a miracle answer. I'm just hoping not to get conned out of paying a boatload for diagnostic work on my next maintenance.
I'm familiar with the actuator noise, and it doesn't appear to be that. The pace is much slower, maybe 5-7 clicks across 1 second depressing the brake pedal fully.

 

less of a buzzing.
more like this:

I guess that solves part of the question. most likely something to do with the pin or assembly?