Hi Vic,
A VPN is just a secure tunnel between your computer and another computer (or Server) the vpn's listed above allow you to connect to there server securely and then emerge onto the internet from there 'address'. when you emerge onto the internet from a VPN you are essentially anonamous.
This will bypass your secure connection to your internet service provider (BT, Sky, Plusnet etc) so they cannot monitor what you are doing, which they are legal obliged to to store details of.
In this situation there is not really a security benefit, the VPN just anonamises you.
However if you normally use your computer in Cafes, Airports, hotels etc there is a security threat that your connection to the internet could be compromised and/ or monitored (not good if you check your bank account for example).In this situation a secure connection to a VPN is of great benefit.
This is a basic explanation, there are a few details / caveats I've omitted for clarity. I you decide you want a VPN I would choose a subscription one (i use PROXPN)
There are a couple of recommendations to improve your security / browser performance for free.
install a browser extensions called
'ublock origin' it will stop all the crap that webpages load (adverts etc)
'HTTPS Everywhere' this will try to force the browser to always make a secure connection to a website (some websites allow both secure and insecure).
Quad 9 is also a good call!
If you pay for an antivirus, consider using the free one in windows 7 , 8 and 10. its more than good enough.
If you have any questions please just ask!
Regards
Paul