I would recommend that you avoid any free VPN's, as they cannot guarantee 100% anonymity / data security etc.
I've personal experience with Express VPN, they offer a 30 day money back trial. If you are not happy with the VPN you can get your money back. It works well for Netflix / Torrenting etc. and includes an automatic shut down mode - if the VPN drops out for whatever reason it will block your Internet traffic, protecting your anonymity (other VPN's do this too). I paid around 5€ per month for 15 months (you can find discounts fairly readily).
Surfshark is a lower cost option. If you sign up for 24months its around 1.50€ per month.
NordVPN used to be the most popular VPN until recent security breaches (2019) brought into question the overall security of private data.
There are others, however as I've said, I only have personal experience with Express VPN, but have had no issues with it.