This deal is offered as a New Year's celebration - a way to start off 2012 on a positive note. Unfortunately, these emails do contain links that must be followed to activate the 50% off coupon in your game, so you won't be able to just load your farm and magically see the offer appear. Sure, offers are currently going through rotation, but these currently contain free-gifts-with-purchases, rather than an actual discount on Farm Cash itself. Also, not all players are receiving these coupons. It could be that they're just being sent out to the game's most active players, or perhaps those that have purchased Farm Cash in the past, but either way, you'll need to keep an extra special eye on your inbox until the end of the week to make sure you don't miss out on your chance to score extra Farm Cash at a fairly reasonable price.
You'll be able to redeem your coupon until the end of the work week, January 13 at 11:59 PM EST. The coupon applies to all Farm Cash and coin packages, so it's at least worth looking before turning down the opportunity altogether.
Did you receive a 50% off Farm Cash coupon from Zynga, or are you still waiting? If you received one, have or will you use it? Sound off in the comments.