When I started researching cloth diapering I didn't know what kind of budget I would have. I didn't have a lot of money to spend, so I knew I would buy used. I checked out craigslist and saw a couple people selling some diapers for around $100. Compared to the $700 we would be spending on a year's worth of Seventh Generation diapers, that seemed like a bargain to me!
We were lucky because we found a huge stash of fitteds for $50, and then I got six covers from sellers on etsy for about $45. We used those for awhile, then I won a couple Fuzzibunz, then I bought 10 more at $10 a piece, for another $100. When I wanted to get more pocket diapers, I traded out some of the fitteds, seeing as they were sitting in a box in the closet! I ended up trading for another four or five pockets without spending any more money than the original $200. I think that's pretty amazing, if I do say so myself!!
I am such a bargain hunter and I buy most things used, so to me, buying used diapers just made sense. We have a one year old who I don't really want to be in diapers for too much longer, so I didn't want to go nuts on all the fancy cute diapers out there. If money weren't an issue and we were going to be cloth diapering for longer, or for more kids, I would definitely get some of the cute ones, though! So many prints and colors and different types, it makes my head spin!
You can spend as much or as little as you want, it's really all up to you. Prefolds and covers are super cheap, buying used is cheap, or you could go full on and buy all brand new expensive kinds. Either way, I swear you'd spend less than the disposables, which is awesome!! And you can sell them when you're done, or use them on another kid. Can't do that with sposies, can you?!