Only the 2013/04 Quarterly Pack is available via the
Canada Post website, and only this one should also be available at postal outlets.
All other quarterly packs were taken off sale on December 11, 2013, along with all Permanent(tm) stamps due to the pending rate change.
Here on the prairies, it is hit and miss finding the 2013/04 pack. Some post offices are selling them, others are out of stock, and others refuse to sell them because their "manager said so".
I
suspect that they will be back on sale as of March 31, 2014 after the new 85c rate takes affect (with a price increase on the packs of course to allow for the new rate).