My partner and I moved back to the Bay Area three years ago with "learning to sail" as one of our primary objectives. We both got certified at OCSC for basic keelboat and basic cruising. I am a 25 year coach by profession and can say that the instruction and professionalism at OCSC was the best "coaching" experience I have EVER received.
We did not join OCSC as members as this was not financially viable, though we would have if we were more solvent. What we did was join the Lake Meritt Boat Club, which is administered by the Oakland Parks and Rec (go to Oakland Parks and Rec website under Boating). With Basic Keelboat and Basic Cruising certificates you can have access to eight keelboats which are kept at the Jack London Aquatic Center on the Oakland Estuary. Three of the boats are wonderful folkboats and there has been a lovely 26' Ericson recently added. All this for about $665 for the year and there are only about 35-40 members, so you are never without a boat to sail. The boats are older but pretty well maintained, but are not without an interesting problem or two to solve

. After learning at OCSC in the "slot" winds of 10+ knots on almost any day, sailing in the Oakland Estuary at first seemed boring. But you learn a ton about navigating in a commercial waterway, light wind, motoring and docking, etc. We have been doing this for three years and having a blast without spending alot of money. The club recently has started allowing folks to take the boats on overnights in the bay. Sorry no muti-hulls.
I wholeheartedly advise spending the $$, taking the sailing lessons with the best school you can (OCSC in my opinion), then going from there.
We also got on a crew at the Berkeley YC on the Friday night races in the summer and learned a ton.
PS...We are headed to Croatia in March to buy a boat and sail the coastal islands...so just take the pluge!!! Good luck.