I bought some preloved nappies to keep costs down so I could try a variety of different types of nappies.
I got some from someone on here who was selling some of their stash, but you can also pick them up on ebay or the classifieds on the cloth nappy tree website.
Not sure about buying 'unbranded' nappies as such as I am yet to use any nappies at all, but have to say I have been looking at some of those ebay ones from China etc.