So the consensus from the last three weeks of research is that if as retail investor you would like to take exposure to oil (going up or going down), the best bet is USO. An ETF that is relatively liquid compared to other ETFs and ETN’s. And as Seeking Alpha points out keep an eye out on the 5th, 6th and 7th of every month.
The other reason why I like USO is the liquidity and open interest in calls and puts on USO across out of money strike prices on both. If you are in a rush to blow up and wipe out capital (as I am on most days), options on USO is the way to go. They will be taking about me for years to come.
If you are new to option trading please tread carefully and do your home work which involves taking the derivative crash course for dummies, the derivatives master class and the option trading strategy guide and playing in sandbox mode for the first few trades so that you understand how lethal a combination these contracts make with ignorance.