What I decided to do was to buy several nappies to start with, of a couple of different kinds, and then see what worked best and buy more of those.

I used a prefold+cover exactly twice. I didn't like the way they got so soaked and seemed to me to be going to rub DD's legs raw any minute. Though it's clear that prefolds work for lots of people with small babies, and they are certainly cheap. We're now getting good use of the prefolds as change table liners to catch spills, so not wasting them, but I'm glad I didn't actually buy them myself (they are loaned from my sister), as they wouldn't have worked for me as actual nappies.

I bought a "trial package" of baby beehinds that included a couple of their bamboo fitteds and a minkee magic all-in-one. And I bought a handful of bumgenius AI2 to try too. I've ended up buying more of all of those nappies, as they all work well for me, for different situations (night nappies need more absorbancy, nappies to take out in the daytime need to be easy, clean, and fast to handle in strange change situations like public loos or the park, etc).

Some of the things I did right (for me, YMMV) were:

- have a couple of different kinds (we actually have 3, counting the two different BBHs), but not more than that, because it's too confusing, especially for DH

- buy nappies in large enough amounts to get a discount, small enough to have not committed enough money to be really upset if they don't work out

- buy nappies that have excellent reviews, rather than trying to save money on something that might not work as well

- wait to see how many I really needed before buying lots more. For a newborn, washing daily, 18 is enough nappies for me. I didn't need to buy as many as 30, which was suggested somewhere I read about them.

- use disposables at first (because you'll probably be in a state of shock about the whole baby thing, at first, and whatever saves you time is worth it for the first couple of weeks). I was particularly glad of this as I had an emergency caesarian that I totally didn't expect, so a more difficult recovery than if the birth had gone better.

- Disposables are also a great idea to have to hand if you run out of nappies in the first few weeks because the newborn just pooed that many times that day (which they can). They get a lot more regular, and need fewer changes, after a few weeks. We only used 7 nappies yesterday (that's a record low, so far, at 7 weeks).

I reckon that buying some nappies to use as trials at first, and also putting aside whatever you can each week so you have money to hand to increase your stash when you know what works best for you, is a great idea, if you can manage that. Also the prefolds + cover are worth a try, especially if you can borrow some from someone, or buy a small number not a huge bunch. Both my sister and my best friend swore by them (I'm actually puzzled by how they don't seem to work well for me).