Lol unlike Amsterdam our Dispensaries aren't legal cafes. They are to give ill, Medical Marijuana Cardholders their medicine.
Long story short, you need a doctors recommendation to use cannabis or be allowed in a clinic in the legal states. Unless you know a clinic owner... try getting your card while you're in SoCal though. ~$150 then go hit up all the dispensaries your heart can desire!
Anyways...
http://www.canorml.org/ has everything you need to know about your rights and how to get a card. If you feel like taking a little trip from San Diego to Long Beach you can get your card for $100 this summer at the place I got mine. Takes about 20 minutes, lol.
EDIT: Forgot a few other questions you had... the headshops are everywhere and legal. They sell them as "Tobacco/ water pipes" so you can do whatever with those. It's paraphernalia, but you can take it with you in a bag fine. Don't raise any suspicion. But if you want to haggle and see every kind of fucking piece and pipe and bong and vape... take a drive to Venice Beach. Walk the strip and go to every head shop, keep telling them the place down the street sold the same thing cheaper. I got an $300 vape for $140 if that helps lol.
Not to mention the Venice boardwalk has two clinics with doctors writing recommendations for $100. You could kill 3 birds with 1 stone... get your card, buy a piece, buy some weed from a dispensary. All on the same strip of beach hahahaha.
Also Venice has a Hash bar. Best place I've ever been to. Illadelph bongs with frozen coils n shit. Bomb fucking hash.
