Those motors should start rotating when power is applied or at least when given a small rotation. They may be faulty already and may need new brushes.
A possible source of motors is car wrecking yards.
A typical motor would be the one that drove the car's windscreen wipers or the fan motor for blowing air into the car.
These are quite powerful motors and built for a very long life, so they may be working even on a car that is very old.
These motors are better than the ones from mains voltage
power tools because they will operate on 12 volts which is much safer than playing with mains voltages.
It is possible to make simple motors yourself (Google "DIY Motor") but they will usually not be very powerful or efficient.