Wrong. It's not free gas. They PAY YOU to take the gas!
hah So what happens is this. People trade futures contracts to make money. As I noted earlier, back when I was working for a broker who traded them. You could buy them and sell them and just settle for the price difference. You didn't have to take delivery of the actual oil. Dodd-Frank changed that. No longer could you do that. Whoever held the contract at expiry, had to take delivery of those contracts!
So what happens is this. Trader A) buys 50 "lots" (a "lot" is basically 50 barrels, 50 lots, is basically 2,500 barrels) of oil futures contracts (WTI options) for say $39/barrel ((39 * 50) * 50 = $97,500 Then he sales it at a profit for say $40/barrel which comes out to $100,000 or $2,500 profit.. That guy holds on to the lots with the intend to sell it again as the maturity date gets closer.
All the sudden the price goes from $40 to -$20 per barrel. How does it get to -$20 a barrel? Because the trader cannot take possession of the oil. He has no place to put it. So he has to PAY someone else to take the oil he bought! So, he spent $100,000 for the oil, and then had to pay someone $50,000 more to take the oil off his hands!
So him purchasing that oil pre-crash cost him $60/barrel or $150,000 for all 50 lots!
The guy that ended up with the oil made $50,000, plus he can hold that oil until the price goes back to say $40/barrel and sell it for $100,000! He basically just accepted $150,000 Fo' Free! The trick is, you have to have a place to store 2,500 barrels long enough for the price to go back to $40/barrel.