

Their website has a convincing reason why:

Short Answer: No, there isn't a free option. You can add time to your account whenever you want, using whatever payment type you find suitable at the time. There are several accepted forms of payment, from traditional methods like credit card, a bank wire, PayPal, giropay, and Swish, to cryptocurrency, physical voucher cards, and even cash. That said, there might be discounts if you buy through a reseller. If you buy one month, it's 5.00 EUR, but if you want to pay for more than that at once, it's still the equivalent of 5.00 EUR /month (e.g., ~60 USD for a year). You pay for however long you want the service.

There are new-user discounts and odd subscription lengths, making it tough to decide which tier to go with. Not only does that service have multiple subscription types to pick from, but each has its own set of prices, depending on how much you want to pay up front. A great example of this can be seen with NordVPN. Most VPNs list gobs of options when it comes time to pay.
