Gamze:

I have used one-size and I liked them; however, I didn’t start using them until my kids were older. I don’t know, aruond 3 months probably? Until then, you almost have to use something smaller. The one-size aren’t really going to work the whole time. They will work a whole lot of the time, but not the whole time. You’ll have difficulty getting them to fit a newborn. Now you never know, because it really depends on baby’s shape, not just weight, so you may be fine with them. But chances are you’ll need something smaller at first. You might want to consider disposables for the first few days, just because those first few poops are so gooey and nasty and just yuck. If you want something cheap to get you until the one-size fit, then just prefolds and covers are the way to go.