As someone who grew up in the midwest (Ohio), lived in Cali (Sacramento) and moved to the east (MD) a few years ago, the fishkeeping scene in California is very different than in either the midwest or the east.
While there were fish clubs in Cali (including a good one in Sacramento), their presence seemed a lot less significant than in, for example, Ohio, where just about any given weekend there's a club holding an event, having a meeting or holding an auction.
Since moving back to MD, where there is an active fish club scene (as there was in Ohio), I very seldom need to deal with folks outside of clubs and club events when selling fish, tanks, supplies, etc. Prices aren't always great but much less hassle than dealing with the random time-wasters, grifters, low-ballers and hustlers you often find online.
Matt