Inevitably, your child will grow out of their infant car seat if you decide to go that route. Once you have to permanently install a car seat, I really encourage investing in a convertible seat. It converts all the way to a booster seat, which your child will need as well.
We bought a convertible seat and transitioned to it after the infant seat, but if money is tight and purchasing a car seat for each stage of your child’s life is not an option (or your preference) then I definitely suggest a convertible one.
This is not the type of seat that is easily moved back and forth between vehicles though, so if you have more than one vehicle that you regularly use, you might want to seriously consider investing in more than one seat.