if you are looking for schwag it can be found pretty much anywhere. you will be approached in beach towns by vendors. in San Jose or the central valley then you should head to a place where a lot of kids hang out, like san pedro. its a good idea if you keep 20 bucks in your pocket whenever you are holding, since it is illegal. however a 20 will bribe your way out of a lotta shit.
they have a good mids type herb they call Jamaican. it's harder to find and runs about 100-120 an ounce versus the schwag price of 20 bucks an ounce. the schwag is really really bad though.
as for nugs....you gotta know somebody....
and prices are similar to the usa.
all depends on what your lookin for.
let me know if you have any other questions.