Spoken like a true Albertan oil-baron!

My problem is that the price stays at 75.9 for months and then jumps to 80.9 for a week and then 84.9! what causes this? Why do all of the stations do this at the same time if they are all supplied by different refiners? It reeks of price-fixing to me and I'm pretty sure that there's law against this sort of thing.
PS: If my car ran on CocaCola, I'd really start complaining! Imagine a bottle deposit on top of the price of a fill-up?