We didn't start using our one-size diapers until DS was probably about three months old or so. I also didn't want to spend money on a newborn stash that was only going to last for a short time, so I did a newborn cloth diaper rental package through a local store. I think it was around $75 for 24 size 0 Kissaluv diapers and three covers, and I kept them for the whole three months.
It looks like there are similar packages available online, so that may be worth looking into as well. I had mixed feelings on the Kissaluvs themselves, but I loved the idea of being able to rent the diapers!