Amazon.co.uk offers Battlestar Galactica: The Complete Series on Blu-ray for £30. During checkout, it drops to £25 (~$50). With £3.08 (~$7) for shipping, that's a lot less than what Amazon charges in the U.S. and the lowest total price we've (Dealnews) seen. 1
Region free.
Estimated delivery: 13 Dec 2014 - 18 Dec 2014. Makes a good Christmas present.
Other retailers:
NZGameshop $97
WowHD $121