As far as I know, Proton has a free period for the first week, then you must buy premium access, or you will be able to use only a few of the services. But if you want to use all the features of a VPN, you need to buy full-time access, it's obvious. As for me, I use Express VPN. It's very convenient, and I think it's not so expensive as the others. For example, you may buy 6-month access which will cost you almost $56. You can also buy whole-year access which is worth almost $100. The most attractive thing when choosing a VPN was that Express has 30 days money-back guarantee. But I was assured I will buy it even after a few days of using it. You may find all the necessary information about it
Pinpoint VPN here.