I assume you are in CA?
Vending to clubs is a legal grey area. It is obviously done all the time but it will never be 100% safe. You are only allowed to possess 1/2 lb in LA (depends on county/city) however if you are vending I'm assuming you will have more than that! Also cultivation is really supposed to be for personal use, you can technically of grow more if you are operating as part of a collective BUT if your plant number exceeds the set county (or state limit if one is not set by county/city) limit the cops will most likely bust you and let the courts decide. It will be up to you to defend the legality of your grow (not a fun process).
Also collectives and growers are supposed to operate on a non-profit basis so if your "vend" is interrupted and money is exchanged, even if you truly didn't make a profit you will likely be charged with intent to distribute.
That being said it is done all the time, just be aware of the risks!
Side note- I spoke with my lawyer once about 99 plant grow permits, they are scams and do NOT hold up in court!
Not sure about vender permits, however I would assume they fall in the same boat...