I use NordVPN but i'm not super anxious to recommend them. There seems to be some controversy about who ultimately owns Nord, plus they are a huge player in the VPN arena and i figure that makes them a target for the "intelligence" communities. I will probably switch to Mullvad when my Nord subscription expires.
Nord has writers (or contributors perhaps) that write about various tech stuff and some of the articles are really crap, however their latest one, 7 common VPN myths debunked, is well worth a read. It starts off by debunking the myth that 'free' VPNs are just as good as those you pay for and they are absolutely correct. One should NEVER trust a 'free' VPN provider! Operating a VPN service costs a lot of money in hardware, bandwidth and support and i'm sure there are many other expenses as well. Any company that claims to provide a free service is making money somehow and that 'somehow' is likely through data harvesting and advertising. Such providers obviously couldn't care less about your privacy which is the whole point of using a VPN.
As the author, Anna Rasmussen, states in her article:
As VPN myths go, this one is particularly dangerous to the average user. What you must always remember is this: when a for-profit company provides you with a service for free, that’s because they are using you to make money. You are the product, not the customer.
Anna also correctly points out that paid VPNs are not necessarily trustworthy either and that doing your own research is crucial. You can find some resources in my article, Tor verses a VPN - Which is right for you?.
Being a Firefox user, it pains me to see the plethora of 'free' VPN extensions that exist for the browser on the AMO website. It is disgusting that many of these companies are even allowed to advertise on AMO, not to mention that apparently millions of gullible people people are using their services.
A 'free' VPN is like a 'free' email provider, or a 'free' social media platform; It's 'free' because YOU are the product.