Seems it's spyware. I would recommend downloading superantispyware or malware anti-malware software. You can check more tips at:
or you can find manual removal instruction of this spyware at:
Oct 26, 2016 - If your web browser is randomly being redirected to the “Best Coupons” pop-up ads then it is possible that your computer is infected with an adware program..The adware responsible for the Best Coupons pop-ups is bundled with other free software that you download off of the.