An LLC does not offer any outright tax savings, but it is a flexible entity that could choose to be taxed in a different and potentially create tax savings.  An LLC offers legal protections if the client can manage to prevent commingling.


You should talk to an attorney (ask me for a referral) to discuss the legal liabilities of the business. 
LLC/Corporate compliance can cost an average of $3,000 per year. 

You could start as a sole proprietor and when you have high enough profits consider forming a separate entity. You could still write off necessary and ordinary expenses; you can still get an EIN number for free on the IRS website as a sole proprietor. 

I have attached some information for your reference. 
https://www.ftb.ca.gov/file/business/types/limited-liability-company/index.html
https://www.irs.gov/businesses/small-businesses-self-employed/apply-for-an-employer-identification-number-ein-online

When deciding to form a corporation or LLC, it is important to keep the 15-day rule in mind.

The 15-day rule only applies to short tax years that are 15 days or less.

The 15-day rule states that inactive business entities (Limited Partnerships, Limited Liability Partnerships, Limited Liability Companies, and Corporations) with a tax year of 15 days or less are not required to file a tax return or pay the $800 annual/minimum tax if they meet both of the following:

They did no business in California during the tax year
Their tax year is 15 days or less

https://www.ftb.ca.gov/about-ftb/newsroom/tax-news/december-2020/all-about-business.html