just fix the POS car that you already have.
you might have to take the bus for a week or so and walk a bit whilst you save up a bit more money, but to be honest it'd be better to look like a retard than to skip school and miss out on anything that might be important.
driving with Bald tyres is dangerous. but you might not have to get new tyres, you might be able to get some 'fairly' good condition tyres at a scrap yard for a lot less.
the best bit about that is that you can just take the wheel rims as well so you won't end up having to pay for fitting them either.
(just drive to the yard and swap the wheels!)
The manifold hole is not dangerous, but it is something that'll be an annoyance, are you able to fix the hole, or will you need a new Manifold?
the thing is that if you have a car, it might be a big pile-o-shite, but when you've only got a hundred bucks to get another car you should probably go with this saying, "better the Devil you know than the Devil you don't"
or in other words, don't waste your hundred buying another POS that can sit rusting next to the first!