Legal Question in Criminal Law in California

I assume you're talking about a medical marijuana collective.

The first step would be to establish a fund for your legal expenses, recognizing that you could wind up facing criminal charges no matter how careful you are in setting up this cooperative in the first place. I'd suggest a minimum of $50,000 for each person involved.

Keep in mind that medical use or cultivation is only a defense which can be established during a trial; it does prevent the police from arresting you, or the District Attorney from prosecuting you, if they believe you are operating outside the law. In addition, marijuana remains illegal under Federal law, despite California's medicinal laws.

Like most ballot initiatives, Proposition 215, which legalized medicinal marijuana in California, is constantly being reexamined by the courts. Law enforcement attitudes are also changing; the Los Angeles DA had ignored storefront dispensaries for years, but recently started busting them, claiming they were diverting some of the marijuana they sold for non-medicinal purposes.

It would be reckless for any attorney to try to give you comprehensive advice in a brief-answer forum like LawGuru.