Hi,
There are a lot of different types on the market, to break it down a little there are
Fitteds: Sized nappies like terries etc which are covered with a wrap. An example of this would be a tots bots bamboozle and a Motherease wrap.
All in one: These nappies are closest to a disposable, you literally pop the nappie on and when wet you pop the nappy in the nappy bucket. An example of this would be a Bumgenius organics or a tots bots easyfit.
All in two: Like an all in one but the inners can be changed when they're wet and you reuse the shell more than once. An example of this would be an Itti bitti snap in one.
Pocket Nappies: These nappies are like a disposable but instead of being like an all in one you have to stuff the pocket of the nappy. These are good as if your baby is a heavy wetter you can boost the absorbancy to suit your baby or for overnight. An example of this would be the Bumgenius Pocket or a wonderoo v2.
Here is a guide to some of the different types of nappies.
What I would suggest is to buy one or two trial packs and after using them decide which nappies you like after using them on your baby. You could end up paying out for an expensive birth to potty pack and find that they don't suit you or your baby.
I would totally recomend them myself, we use bumgenius pockets on my DS. But I tried a few different types before settling on these ones. Yes the initial outlay is a bit much, but personally I'd rather spend that amount of money now than have to buy nappies every week eventhoughIhaveaseriousclothnappyaddition. 
Another thing is you can buy nappies preloved from places such as cloth nappy tree or the used nappy site. I did do this and have ended up spending a lot less than what I would have originally.
Anyway I hope that helps a little.