Employers get to deduct health care premiums from pre-tax, whereas freelancers have to pay for premiums out of their after-tax income. It can make a fairly big difference if your marginal tax rate is high (which it probably is in CA).
The opposite is true. If you are a freelancer, healthcare premiums are an above-the-line deduction, which practically has the same effect as a business expense. This is better than a regular deduction because you get it even if you don't itemize deductions. See https://turbotax.intuit.com/tax-tips/home-ownership/deductin...
The problem is you literally can't get all the benefits that a big company can negotiate.
Why not use a website like groupon?
That's more of an issue with the healthcare industry and insurance companies.