My .02.

You can't do this "cheap" using your own platform..for example your own website.  The bandwidth required would chew through your profits very quickly.

If I was doing this, I'd choose YouTube Live over Facebook Live.  That's my opinion, I just think it's a better platform for this sort of thing. Facebook live for the most part can be sketchy as far as quality.  IME Youtube performs better.

She could also mark up the page a little better, save the videos, so that clients could come back to them later.

HOWEVER....if she chooses YOUTUBE, tell her to sign up now... It takes 24 hours to activate the streaming account.

With Youtube live, she can have multiple camera angles directly through YouTube all she needs to do is sign into the live stream with multiple devices (Up to 6)

Then all you need is a RODE iPhone microphone and you're off to the races.

I'd forwarn her...This is not something that you just sign into 5 minutes before you're about to do it.  Sign in and check it out for a coupe of days.

That's your easiest way...She's only limited by the amount of Tripods and devices she owns.

Not to mention, Google owns Youtube..so Youtube is a search engine.