It depends on your policy, and what you mean by a 'broken' oven.
Some policies cover motor burnout, but that can also be restricted to burnout caused by faulty power supply, not by age (low current/voltage supply makes fridge motors burn out on startup for example).
But what's actually wrong with the oven? They are usually pretty simple devices. I've had to replace the cavity fan ($100.00) and only this week the selector switch ($80.00) on our SMEG.
How old is the oven? Still under warranty?