There are plenty of free VPN service available on mobile device. I am listing here those that you can configure on your Windows, MAC OS or Linux system
Windscribe
Pro
- offer 2GB/month without confirming your email.
- 10GB/month free when you confirm your email address. I suggest you to use a fake/disposable email if you want to enjoy larger bandwidth.
- Refer a friend to get additional 1GB/month. Use my refer a friend link if you are keen on getting extra GB but you need to confirm your email before you get the extra GB. You must register via browser and not from the apps you download or you won't get the extra 1GB when using my refer a friend links.
- Free Windscribe support p2p as well.
- Free plan allow access to 11 locations
- Provide step by step guide at their website on how to configure on Windows, MAC OS and many other Linux distributions.
- As of October 2018, works with Youtube, Whatsapp in China
Cons
- You are limited to the free bandwidth allocated to you on monthly basis.
VPNBook
Pro
- Doesn’t have any bandwidth limitation but
- No registration required and therefore completely anonymous.
- VPNBook support openvpn and so far has been free for many years.
Cons
- Its password gets changed every few weeks.
- No p2p support for US/CA server.
I won’t be listing other VPN that offer free for limited time as I presume if you are looking for free VPN won’t be planning to sign up for paid VPN.
This video shows a step by step guide on how to configure VPNBook on Kali Linux using OpenVPN
This video shows a step by step guide on how to configure Windscribe on Kali Linux