Ignoring everything else about this bike, I wonder why the crank arm is missing. It's likely the BB taper has been ruined when the arm fell off. Add a new BB to the price of fixing along with the tires and crank arm.
Originally Posted by
FastJake
A pedal from any bike should work. That bike will take 9/16" pedals, so just make sure you don't get a 1/2" pedal. 1/2" pedals are less common these days but they still exist on some bikes with 1 piece cranks.
That's what I thought until last week. A customer brought in a bike with a 3-piece crank which used 1/2" pedals. I didn't know such a thing existed.