UHT milk can be found in most Canadian supermarkets. It is usually located in the bakery isle near the milk powder. It could also be labelled dairy beverage, milkshake or other diary product name, depending what has been added or deleted to the basic milk source.
The convenience of UHT milk does not come cheap, compared to a 4 L pasteurized milk $4-4.60 average at most places. (Ontario).
Here are some brands and prices we found.
2 Lt - 2% UHT Milk. I called Parmalat to ask where their U.H.T. milk is sold. Customer service could not answer this and was unsure of the product. Must be a big seller!
Update: 28/3/14 Beatrice (Parmalat) 355ml white or chocolate $ 1.25 at Dollarama in Ontario. - Product of USA