1 mil works fine for me, (made tons of covers, AIO, and wetbags) It's cheaper then 2mil and I don't really see that much of a difference.
http://www.diapershop.com has good prices and great selection and I like
http://www.thefabricfarm.com they have
some really good deals on small amounts. I prefer non DWR, but if you don't mind it
http://www.janellespuls.com has a good selection too.