I’ve been beta testing Blockr for a while and I’m very impressed. Unfortunately it is a paid app. (When my beta build expires, I will be buying it)
If however you’d like a free content blocker for iOS, have a look at Freedom. It isn’t currently available in the US app store but it may be available in your location. It doesn’t rely on in-app purchases to grab a hold of your money. It really is free.
If you don’t mind handing over a few dollars, I can’t recommend Blockr enough!
Happy browsing (without being tracked and without adverts)