I know they are supposed to be cheap, I would love to have one but could not afford it even if they were legal in California. You can actually own one in California if it has a ten round magazine that can only be installed or removed with a tool and can not be switched to automatic fire. It also can not be equipped with a pistol type grip.
You can not carry it anywhere in public without it being in a locked case, the magazine removed, and a chamber lock installed as well.
If a neighbor sees you carrying it or say cleaning it on your patio, and calls the cops saying that she might have felt threatened, you will be arrested and your weapon will be confiscated.
California insists that these laws in no way infringe on our right to keep and bear arms.
-John