This question already has an answer here:
I've been considering a VPN tunnel, specifically PIA.
These types of companies make bold claims of complete anonymity and privacy, with no one in the world (ISP's, governments, school or corporate network monitors, no one) being able to know the contents of your web traffic.
Simply put, are there any hidden gotchas? How can such a thing exist for such a relatively low price and truly be that secure?
And of course, let's ignore the gotchas of "VPN's log your traffic" (let's assume you've chosen one that doesn't) and "the encryption could always be broken" (let's take difficult to execute exploits off the table).
I'm concerned about this for a variety of reasons. I don't want to be profiled by corporations; I have political and social leanings that I don't want to be uncovered both by governments and just anybody; I don't want my peer-to-peer activity throttled or inspected; etc etc. I just don't want my activity used against me by anybody.
I of course am doing only ethical things :)
A narrower version (tell me if I should ask a separate question): are VPN's effective at hiding activity from "localized" gateways like an ISP or a school/corporate network?