I use this - went to the link & not bothered by ads:
Adblock Plus is a free extension that allows you to - among other things - block annoying ads, disable tracking and block domains known to spread malware. Available for Android, Chrome, Firefox, Internet Explorer, Maxthon, Opera, Safari and Yandex, Adblock Plus uses filters that you choose to block all unwanted elements.
Try “uBlock Origin”. Freeper NewFreep suggested it as an Adblock Plus alternative and I think it has made my Firefox much more responsive.