Use it. Love it.Central place to see all of my many CC spends at once and to catch if anything is awry.
is it free?
Yes.
how do they make $
To keep tabs on budgeting, fraud alerts, just for kicks, etc?
Is it as safe as online banking?
see here.https://www.mint.com/how-it-works/security/
We've got at least one thread on this already, possibly more.