If you're worried about analytics and tracking / ads on your iPhone, consider installing Disconnect's Privacy Pro:
https://lifehacker.com/disconnect-pro-eliminates-tracking-on...
It costs a few $$, but sets up a VPN profile that is generally always on. It just blocks all of the ads / "web bugs" / analytics stuff and gives you a UI to show how much. Apple cracking down is a good thing, but so is defense in depth. It estimates that it has blocked 8Mb of crap being downloaded on my phone just today.
While the concept is good, I'd be extremely concerned of using any third party VPN service, free or paid. You are basically trusting your entire internet usage to a single entity, and I think this is way too risky.
One alternative is setting up a raspberry-pi at home running pi-hole and OpenVPN. While it is still not risk-free, it is still better than one centralized entity taking everyone's traffic. On the other hand, setting that up is still not absolutely straightforward, but it is getting better.
I agree.
“Don’t like being tracked? Just let us watch EVERYTHING you do and we promise to stop people from tracking you.”
You’re putting someone in the perfect position to track you far better than anyone else could. You better REALLY trust them.