Fake Microsoft or other Tech Support pop up

I have customers that keep getting fake tech support pop up adds that hijack the browser.
These can be from Microsoft, Norton, Comcast, etc.
Is there a program that is effective at blocking these hijacks and not break
the bank?  Free ones are always good, but don't like the upgrades they try to get you to
do.  So if there is a good paid program, I think they would like it being add free.
Thanks.