An alternative way to remove the crank is to leave the fixing bolt off and go out and ride the bike around a nearby hilly loop until the crank comes off under
pedaling torque. Not the best way but cheaper than a gear puller.
I don't think it's cheaper than the correct puller unless you plan to replace the entire crank anyway. A square taper crank "removed" that way will have the square recess distorted to the point that it will never fit properly again.