Mullvad VPN may be a good choice and the good thing about it is usually fixed price of 5 pounds even if you buy for a single month or for a decade
Yes it's cheap but there are other VPNs like express VPN that give you good discounts if you buy their yearly subscriptions etc but still, they cost you more than 5$ a month. However, I just wonder why they aren't as popular as Nord or Express VPN? Do they (express/nord) offer extra services etc
This comes down to the same logic as asking: why isn't Linux as popular as Windows because it is open source and more secure?
Why isn't Bitcoin as widely used as central bank currencies, even though it is completely free money?
I chosed NordVPN because it had a very interesting discount, I think it was 70%, so I took advantage of the 2-year package promotion.