How much is all the expenses to be paid upfront to join in a Real Estate Company in California?

It depends where you go, some companies ask for a monthly desk fee, E&O Insurance, ect.
Your also going to have to pay for your MLS.

You will have to pay for your membership into the NAR, CAR, and whatever local Realtor association you are in too. These are usually annual or semi-annual dues.

Office fees will depend on which company you decide to choose. Every franchise/office is different from one another. This is one of the major factors you will want to find out when you go and interview with multiple companies before choosing one.