At the time of this writing, the New Years items in the game's store will expire in a little under 5 hours. The prices are the same as normal, so unfortunately there is no sale here to entice you to buy these items before they're gone. It's presumable, then, that the simple fact that the items are going to expire will be enough to convince someone to do some shopping, but that's up for each individual user to decide.
As a recap, you can purchase clothing items for your avatar like dresses and tuxes for 10 Farm Cash, one-time-use Fireworks for 3 Farm Cash, an animated Cider Fountain for 15 Farm Cash, and even animals like the New Year Horse, and my personal favorite, the Disco Ball Sheep for 22 Farm Cash and 140,000 coins, respectively.
Once these items expire from the store, it's presumable that they won't be released in the game again, or at least not until the New Years celebration begins leading into 2012, when Zynga may re-release them temporarily. If you don't want to miss your chance at any of these limited edition items, make sure to shop now while you still can!
Have you already purchased the New Years items that you were interested in in FarmVille? Let us know in the comments.