I've only just started using them, and asked about them at our local nappy project who were brilliant and gave me a trial hire kit to see how I got on with them.
1) Brand, I really like tots bots, have 5 v1 all in ones, one pocket tot and one v2 easy fit all on one. I like them all and would love to up my collection of easy fit v2's. I also quite like fuzzi buns pocket nappy but not the one size as it has leaked every time I've tried it.
2)Ebay, tesco, there are literally hundreds of websites with different types etc, it's quite confusing which is why I stuck to tots bots after liking them. Ebay don't allow the sale of used nappies though, but there are sites like nappy tree which do.
3) January, when lo was 7 months, because the price of disposables had gone up so much I decided that I'd had enough! Next time I will start earlier but maybe not with a newborn...
4) My trial pack had loads of different types so I was able to see what worked and what didn't without spending loads, some just don't fit some babies. See if your local council have a scheme.
5) Washing is much easier than I thought, I'm terrible at keeping on top of the washing but because the nappies HAVE to be done I do a wash every 2nd day of lo's clothes, like others I store them in the net, close it up and bung in with the rest of his stuff, usually on a 40 but every so often on a 60. I also use paper flushable liners and flushable wipes, just because its easier for me (I'm still lazy at heart!) But lo's poo is solid (tmi) now so its easy.
6)It really does become an obsession, there are so many cute ones available, so much for saving money haha, at least my bin doesn't smell anymore
good luck, hope you find some you love

xx