Says it works for new and existing users of LastPass, emailed coupon needs to be redeemed by December 31st 2014.
As far as I know premium allows you to share out access to specific passwords to user groups you create and also lets you use the mobile app versions.
LastPass allows you to securely store the passwords you use for accessing various websites, and also helps to create secure passwords in the first place.
Combine it with free 2 factor authentication for a little added security on your LastPass account itself.
Update: Seems they have now changed the rules as the original offer page now says:
** Due to overwhelming demand, this deal is now only available to NEW LastPass customers **
great timing in view of upcoming iOS 8. I prefers to use inbuilt keychain on iOS and OSX but will give it a try. thanks for the post OP