The problem with a 1-off payment is that when new versions are released, you are probably going to update due to either new features or improved security (or both!). I doubt the upgrade is free, although it's probably around 50% cheaper if you have the previous version?
$12 a year for lastpss seems better value as updates will be free, and no large upfront payment.
How much is 1password for a new user, and also a user whose updating from a previous version?