It seems to be differ depending on location. I just called a Verizon Wireless store here in town at around 3:45 central time (Pflugerville, TX) and the sales associate told me that the Extended Battery was 59.99 but that there was a promotion going on where you get half off. I asked him how long the promo was going on, and he said that it's pretty much indefinite (or until they are told to stop the promo, I guess).
I noticed that the Verizon Wireless website doesn't list this promo at all, but I'm not sure if the price changes once you get to checkout or anything.
I have a cousin who has worked with AT&T, Verizon, and (currently) Sprint. She would tell me about these promos all the time. You'd be suprised at the deals you can actually get in-store. Give your local retailers a call!!