What I used was flanny squares and bamboo prefolds till she was big enough

If you get some bamboo prefolds then you can use them on a newborn and then later on as boosters in pocket nappies or just to lay in others that might need a bit more. Cotton prefolds are good for newborns and are cheaper than bamboo but don't have enough absorbancy to be used in a bigger bub or toddler so while they may be cheaper in comparison they aren't really able to be used for as long IYKWIM.

Cotton flanelette flats are good for newborns and get a lot of use later as burp cloths, change table liners etc.