Staring out without the knowledge of sewing.

I got prefolds on ebay:
From ebay user alpinesilverleaf

I also got some PUL OS covers from
Ebay user fantastic_fiesta

You can also get seconds at
http://shop.clothdiaper.com/shared/StoreFront/default.asp?CS=clothdiape&StoreType=BtoC&Count1=864986598&Count2=782127022

and
http://www.diaperswappers.com/

It is recommended to have 24 prefolds (infants) for a newborn baby
4-6 cover

if you decide on getting fitteds diapers then you will need covers too..