VPN stands for virtual private network. In short it creates a network that protects against snoopers and nefarious types. There are subtleties and some holes. If you have a determined Chinese government hacker wanting to get your stuff then they are going to get it. But that’s not where the threat is, it’s equivalent to a purse-snatcher on the street or the guy going through the parking lot checking for unlocked cars.
I avoid public networks in coffee shops preferring to use tethering off my mobile phone. But that doesn’t mean you should not use them, you just need to use a VPN. So how do you get one and how do you use it? To get access to a VPN you either have to setup your own server that runs the server-side VPN application use a service provider some that you pay for while others are usually ad-supported. For a list of Lifehacker recommended services look here. To get more technical information Gizmodo has a good recent post. But it’s my opinion that you don’t need to know all the tech details but you do need a reliable one that you can use. So select one from the Lifehacker list based upon how often you use a public network and what you use and you’ll be safer.