Why are some cars so cheap lol?

-basically i went ont his website and they had cars for like $300, 400.... are these cars drivable? lol what could they possibly have wrong with them other than a very high mileage ? (most don't state anything, some state missing brakes- how much would it cost to get new brakes?)Blood stains on the seats and in the trunk. Horrific smell of death inside. Brakes would cost $10 canadian