Here is the real deal. Explained by SWIM
If your wifi device is active and you are around random people, you are susceptible to penetration and intrusion. If you are on any connection that connects to the internet, or connected to a local private network that is connected to a server that is connected to the internet, you are susceptible.
Assume you are never completely safe. Like another said, what you should be evaluating is the risk. First of all, what are you concerned about someone having access to? Can you store that somewhere else rather than your laptop? If not, you can encrypt those files when they are not in use so anyone who did access them couldn't use them.
For simplicity sake, if you remotely concerned, download and install "Comodo Firewall". It won't make you invincible, but it will inform you anytime any action is going across your network, and will thwart 99% of wifi hackers. The last percent are unfortunately very difficult to stop, however, they are far less concerned with hacking your laptop. They are far more interested in high-value assets.
To be really honest, you are doing what you need to to stop those that are sniffing around you for something tasty. And the likelyhood of someone hacking you if incredibly slim, aswell, they are likely not interested in anything malicious. Most of your run of the mill hackers are doing it to see what they can do and how to do it. They may look at your data or even in rare cases "mess with you", but most are not interested in anything malicious.
Also be aware of where you are connecting to wifi. If it's a coffee shop and you see 1 other person on their laptop, it's probably a very safe place to use the wifi. If you go to a mall that has wifi and the foodcourt is loaded with people on laptops, that is a MUCH more dangerous place. I'd say it's likely there is someone interested in hacking at the same time that you are if you go there often.
So, overall TL;DR
If you are concerned, get Comodo Firewall software for your computer
-it doesn't make you immune but it will make you aware and stop the average hacker
Pay attention to your surroundings when you are using wifi, if you have sensitive data, you are not safe
If you just use your computer for average things, and you are an average joe, and don't treat computer nerds bad, then you are VERY LIKELY, VERY SAFE.
And no, hackers will not hack you to steal your last few hundred dollars. WAY too much risk for WAY too little return, atleast here in America. Overseas hackers are a whole different ballgame. But you won't see them in your local coffee shop on their wifi. But they can get you at home or at the coffee shop.