Car seat help

FTM.

I have a bit of a car seat dilemma and need some help. So my main question is do you need or what is better.... the type of car seat that grows with the baby from new born to about 90 lbs or the little basket kind that you use for about 6 months and upgrade as needed.

I am asking because we have a small place and small cars and my husband thinks we need both but I feel if we get one good one that is all we need. I keep telling my hubby that we just need an extra base and it will save money and space.

The other issue. We put both of these items on our registry, however my grandmother (bless her heart) bought one of the convertible ones but not the one on the registry. It can’t be used until the baby is 30-80 lbs. My husband aunt bought us the smaller one for new borns and that’s fine.... I just feel it’s going to be a little bit of a waste.

What would you do?