Carseat troubles 😢

So my boyfriend and I are going out today to buy a carseat! We were going to buy one that can go from newborn to toddler, but then found out that most of them are not detachable and cannot act as a carrier.

So should we just get an infant carseat for now and then maybe get the convertible one later on? Or should we just buy the convertible one and a infant carrier?

Also where did everybody purchase theirs?

Thank you for the help guys. It's much appreciated. 😄💜