http://www.norcalduckclubs.com will give you a list of some of the club operators in N. Cal. I'm familiar with some of the clubs/operators on this list. If you wish, you can leave a contact no. (e-mail/phone no.) in my mail box and I'll be happy to pass on the info I have.
I've found the prices depend on location and/or what the operators feels their club is worth.
IMO, now's the time to start looking while there's still moisture in the fields. Although the clubs may be drained, or in the process of being drained, you can still get a pretty good idea what the club will looks like when it's flooded.
Good luck. It's always fun to look at different clubs....