Well, for background I punch the time clock from 5am to 2pm every day for the last 20 years at a cop shop as a "computer guy". Most of you know that already. I started doing "computer" stuff in 1980, with just a short time off to turn wrenches for a living at several new car dealers. I run a VPN at the office.
In a nutshell what a VPN does is make your computer think it is someplace else. In an office type setting usually it is for remote users accessing office "programs", in my case Patrol cars. That is it.
The biggest lie around VPN is the anonymous nature of the VPN. The site you are going to may or may not know the traffic is coming from your computer, but the VPN sure as hell does, and it know just where you are going, how long you are there and likely just what porn you spanked it to. You are living in dream world if you think these VPN companies do not respond to subpoenas. In my setting I can tell just who was doing what and for how long, what searches are made, what sites visited, and what videos are watched.
IMHO if you want to be as anonymous as possible get your internet from a small company, there are very little regs around what has to be kept and how long, this will vary from state to state.
The only thing I can think of a VPN being useful for is if a ball game is not available in your area, or some TV or Movie is not available in your area. For example, Netflix in europe may have a program on it that is not on Netflix in the US. But........
The VPN knows where you are and where you are going, it can also block those sites. There are also lists of "known" VPN hosts that can be blocked at firewalls, along with source countries.
If using public WiFi, Personally I never do. Your VPN will not keep you safe, your traffic to the VPN is over that public WiFi and your machine on that wifi is likely to be hit by someone else on the same network.
If you find yourself out a great deal and "have" to use it, get your self a cell connection, many laptops have slots for SIM cards from the big players.
Waste of money IMHO.