I see no reason to overpay for this when all the features it offers are included in iodéOS, which it uses. You will save a lot of time, money and potentially risk by installing iodéOS yourself on a supported phone of your choosing. It is super easy these days now that all non-Samsung phones support their automatic installer.
Proton VPN has a free plan that is fine if you just want general privacy from your ISP. If you want to do more like torrenting or circumventing geoblocking, there are probably cheaper options although Proton VPN does have significant Black Friday sales (which I think you just missed, unfortunately).