Perhaps a little late on the reply, but if you're seeking an autocross-specific group to join, the Bremerton group (bscc.net) is likely the best bang for the buck around here. Included in the $25 annual fee is a voucher for a free autocross event. They also offer $5 discount off the normal pre-registered price of $30. They also offer some novice schools & a few track days.. ..and sometimes special practice days for members. Membership pays for itself upon attending the first free event!
One would have to attend a whole lot of SCCA events to recoup the $80 fee, so I'd say this would be worth it only if you're planning on attending national events.
As far as stuff, you don't get much from the Bremerton group... no fancy patch or discounts or even a sticker, but for $25 you get a good value over all. It's true that the bscc events often do not go as smoothly as a SCCA day, but sometimes you get lucky & get 5-6 runs!