I agree, don't buy off ebay unless they are a brand.
Keep an eye out on the used nappy sites. I am due with bub in January, I have been keeping an eye out online and have purchased all up 15 nappies and 6 covers (OSFM, mixture of quality brands) and I have paid no more than $200. They are used but in excellent condition, and if i purchased new (I would if we could afford it) it would have cost over $500 so far. Most of them also came with extra inserts, I even bought nappies that were not used, only washed in preparation and were about a quarter of the new price. I will at times use disposables for a break, but I can not justify paying $35 for a box of nappies, plus we can't afford it!!!