Thanks for the info guys.

Long story short, Indy Shop A passed pre-purchase inspection.
Brake fluid light came on. Squealing noise too.
Went to Shop B to do brake fluid flush. They also noted the low brake pads.
Complained to shop A.
They are only charging me parts (305$ for rotors/pads/sensors).
Had they told me sooner, I would've got the seller to comp me, but alas.

Thanks for all the info.
P.S. Brake fluid flush ranged from $97 to $214 in my area..

EDIT: Here is a great video on how to brake fluid flush:
ECS Tuning: How To Bleed Your Brakes - YouTube