This one is open for everyone:
Free Voucher to Purchase Select eBooks from the Amazon Kindle Store for $1
https://local.amazon.com/national/B00AOB51MC
Sign-up for this offer expires December 18, 2012 or when the number of vouchers set aside by Amazon have been exhausted.
The voucher will expire if not used toward a qualifying Kindle book purchase from Amazon.com by 11:59 p.m. PST, December 26, 2012
choices:
http://www.amazon.com/gp/feature.html/?docId=1000857641