I remember being exactly where you are now. :) It. Was. So. Confusing. Then there were these Mom's who'd say, "Oh, it's simple, you just...." Then they'd start rambling in (seemingly) another language. And it didn't help that they ALL had a different answer. So, now that I completely understand that "foreign language", I'm going to do my best not to confuse you further. I ended up using Rumparooz brand. They are the ONLY cloth dipes out there with an inner gusset (you know that thing that is on disposables that always - well almost always - catches the really horrible messes?) Rumparooz has it in a cloth version, so it is even better than the disposable ones. I've never - scouts honor - never had a leak get through one of those bad boys. They are one-size, that was a huge plus for me. I mean if I was going to be shelling out all this money to "save" money, I darn sure didn't want to have to do it more than once. So, one-size to carry me ALL the way through? Sign me up. Not as important, but they have cute prints, and every color one could want. Plenty of choices for boy or girl (or unisex). They each come with 2 inserts right off the bat. I've never needed more. You'll only use the smaller one at first, then switch it out for the larger one, and later you'll use both at once. They even have snaps on them to help with doubling, which other brands do not have. Easy-peasy, my 6 year old would say. Now I did also buy the Lil-Joey's (you'll see this adorable creation if you visit the site). It is the AIO (all in one) mini version of the Rumparooz one-size diaper. It is made for preemies and newborns. Tiny little cloth diapers for if you tend to have small babies (which I do). They are beyond cute, but to be completely and totally honest - not nearly as good as the one-size Rumparooz). I mean they work, but when you have a baby that tiny, truly, disposables work better. So, even though they have got the be the cutest things ever, I'd buy more one-sizes for later and skip the tiny Lil-Joeys. If you have a small baby, use a good (natural or sensitive) disposable until he or she fits into the one-sizes (it won't be long at all - IF you even need to do that). Anyway, I'll stop talking for now. Here is their website:
http://www.rumparooz.com/
Click on the "Shop Now!" link in orange on the top right and look at the diapers and there is a ton of info on the shopping pages. I think you'll like what you see. :) Oh you asked about how many... That really depends on your budget and how often you plan to wash and of course the cycle of your little one. I washed every single day, so I could get away with having less diapers. There is an article on the Rumparooz site to answer that too. I think it may be in the FAQ's section? Just look around, you'll see tons of useful info, even if you go with another brand. :)
Good luck!