Baby car capsule vs convertible car seat

Sue • First time mommy, expecting my baby in late August. Love the nurture community! 😊
Hello ladies,
I am expecting my first baby in a few weeks. We have already started doing some research on baby stuff. For buying a car seat I am a bit confused. I have two options here either rent a car capsule for six months and then buy a car seat. Or buy a convertible car seat in the first place. What would you guys suggest?