The back half of your question is easier to deal with than the front half.
The best prices offered to the consumer are usually the market prices. Competition usually dictates the best price for the consumer at the end of the day. Where there are more players in the market, you see better prices. I know that's a simplification, but for propane that is certainly the case.
I will give you a case in point. In Montreal last summer, I believe, on a propane tank exchange program, it was about 10 bucks in a very competitive environment, as opposed to 20-something somewhere else.
As far as the pricing in Canada is concerned, a lot of the propane is pricing down at Brent. Traditionally, but not necessarily this year, the price of propane has tracked oil. What we're seeing this year, though, because propane is a commodity traded around the world, is that prices are set for it out in Sarnia, at the BP facility in Sarnia, and it goes from there.
There is an excess supply of the product right now, owing to the warm winter that many of us have experienced. You could probably get a pretty good price long term if you were to pursue that for your home or whatever else. That's essentially the way it works.
Some jurisdictions in this country—for example, New Brunswick and Nova Scotia—will regulate the price of propane based on how you offer it for sale and how many times you touch it. If you do certain things, you can add 5¢. If you do other things, you can add 10¢ to the price. However, they use Sarnia as a bench price and they go north of there depending on how it goes. It depends on where you are. In other jurisdictions across Canada—in fact, most of them—it's just a market price.