Any good car seats under $100?? Help me shop 😊

Good morning, I honestly just need help with the whole car seat thing . Im 35 weeks so I don’t have much time . Baby could come anyday but all the baby stores near me are selling them at ridiculous prices $ 300-$400 and I need to buy at least 3 car seats !!! Where would you suggest i should get them from that’s pretty much the only thing I do not have for my son yet.