More info here:
http://www.livejournal.com/shop/perm_sale.bml
Plus, they offer cool incentives like donating $25 of the purchase price to a charity of your choice if you buy before noon PST on December 6th, and the ability to gift your remaining previously paid time to another LJ user.
I'm pondering it. I've been on LJ since 2002, and it's proven useful for meeting new folks, getting info, doing event planning, and keeping in touch with faraway friends.