Sounddude: They probably make/sell more 2L than 3L bottles of milk, reducing the cost of packaging etc and the savings are passed on to the consumer.
There can be good reasons, not all "OMG I am getting ripped off" reasons.
Completely agree with this statement.
Hazarding a guess the most popular size of milk sold is the 2L size (judging by the range at the supermarket). 1L is probably pretty close, and 3L is an also ran. In fact I can't really recall that many places that sell 3L.
If people are really looking for things to complain about then it should be things like a 600ml bottle of coke being the same price (at a dairy, more in a supermarket) as a 1.5L or even 2.25L. Or bottled water being more expensive!
IIRC the raw material cost of making a bottle of coke was about 5.5c, add the water and mix, takes the price to 6c, and add shipping takes it to 19c. Even allowing for the massive cost of plant and labour there is massive money to be made by them - thats why they can afford to advertise and sponsor so much.
Although it pains me to say it, I agree with Labours policy of taking GST off of food, but not just fruit and veg, the the other staples such as water, milk, bread, and meat. And then increase the GST on processed foods to 20%. This would probably hurt me as I love my coke and pie in the morning (breakfast of champions) but it might help making it easier to chose the right thing.