What can you tell me about these Medicare Hotlines as advertised on TV?

What i don't understand is if you get a new plan with

"$0-copay"

"$0-monthly premium"

 plus $140 back monthly from the Social Security.

That means I'd be paying nothing for it.

 So where's the money coming from to pay for the millions-daily TV ads?

Much less my coverage.

They are Insurance agents, that get paid a percentage of the premium. Just like you insurance agent for your home and car.

Medicare is far more complicated than people think. And it will take a Lot of research to understand it.. I am 60, and will start investigating about it in a couple years. You know that you will need Hospitalization and drug reimbursement. And a supplementary plan, but each one has a catch. 

And there are Way too many advertisements on plans to make them all the same. I would start with the Medicare website and possibly go to a local office for help. And go from there

I haven't figured it out yet either.  We got a letter from our supplementary insurance company.  I will be calling them.  It looks like we already have most of the benefits they are touting.