Users who are already have a free LastPass account will now be able to sync between the browser extension and the mobile app. Meanwhile, those users who already pay for LastPass Premium will still have a few extra features like family sharing for up to five users, 1GB of encrypted file storage, YubiKey and other two-factor login integrations, desktop fingerprint identification and the ability to use LastPass for applications. In order to support the freemium model, the unpaid users will see ads showing up in LastPass, so a Premium subscription might be worth the $1 monthly fee just to get rid of the clutter.
Besides saving you the trouble of remembering all your logins and passwords, password managers are an increasingly necessary part of any sane person's setup now that there seems to be a major password breach nearly every week. Of course, even password managers are not impervious to hacks -- LastPass itself was breached last year, but the company has been smart about finding and addressing new security flaws before they cause a problem.