Ask HN: How do I buy crude oil?

I believe oil prices are going to go back up, how do I go about buying some oil? Is there any benefit to using a discount brokerage or can I just walk into my bank? I'm in Canada, does that matter? What kind of fees are acceptable? I have modest investing experience, enough to know that mutual funds are generally a rip-off. I don't have a financial advisor at the moment.

I know it's a bit off-topic but I don't really trust people's opinion on other forums.

Update: I don't want to buy physical oil, just some bits that say I own something that is more or less a direct function of oil prices.