I'm not going to summarize the plot, because you should watch it (the full episode is here). I'll just lay out the essentials. Randy Marsh, Stan's dad, is the main object of ridicule in this episode, as he is in every episode in which he is a main character. His response to the financial crisis is to become the town's ascetic cult leader. Randy orders everyone to be frugal and live a Spartan lifestyle in order to appease "The Economy", who he and his followers treat as a deity. To understand the intersection of morality and "The Economy" in conservative politics, I direct you to my favorite book about everything, Nixon Agonistes. Suffice it to say, Randy perfectly symbolizes conservatives' treatment of the economy as a tool of the powerful, able to be wielded against the poor if and when the poor become too profligate (liberals would say "secure" or "comfortable").** Of course, the less controversial interpretation is that Randy simply represents the Austrian (or Chicago) school, which controlled economic thought before John Maynard Keynes came along and revolutionized liberal economic policy.
The hero of the episode is Kyle, who preaches against Randy's economic theology. Kyle argues that the economy is thoroughly under our control, and we may end recessions with increased spending. But Kyle knows that in order to facilitate increased spending, he must finance the entire towns' debt on a platinum Amex with no spending limit. In other words, Kyle takes on an essential role of government during a recession: economic stimulus.***
But that was just the main plot. The subplot is pretty much one long argument for increased regulation of absurd financial products. Stan has 100 dollars from grandma that he tries to invest. He gives it to a banker who promptly loses it by investing it in a crazy money market fund. At dinner, Stan asks his dad why the economy is in the shitter, so Randy, while enjoying a margarita from a glorified blender called a "Margaritaville", explains that profligate spending angered "The Economy". Stan gets the message, so he goes on a quest to return his dad's offending Margaritaville blender. Lest there are any smartass conservatives reading this going, "But the subplot undermines the main plot! Trey and Matt are condemning profligate spending!" To you, smartass, I would say, "Well, yeah they are having fun with Randy's hypocrisy and with spending money on useless shit. So? Matt and Trey do not take the argument to the next level and claim, as conservatives do, that Margaritavilles and Margaritavilles alone caused the recession. That would be stupid. Again, funny people are not stupid." Anyway, Stan, in his quest to return the Margaritaville, finds that it was purchased on a payment plan. The Margaritaville debts were bundled into a Wall Street investment that went belly-up and had to be transferred to the Fed. But the Fed has no idea how much the toxic Margaritaville debt is worth, so they have built a recession oracle in which a chicken with its head cut off runs around on a gameboard populated with such options as "bailout", "telethon", and "cut education". Needless to say, all of this financial confusion surrounding the Margaritaville debt makes it quite clear that the simple purchasing of Margaritavilles does not a financial crisis make. An entire financial layer cake of confusion and unaccountability enables idiots like Randy Marsh (in other words, the average American) to purchase shit they don't need with money they don't have.
So that's the Margaritaville episode in a nut. It proves that Trey Parker and Matt Stone are not libertarians, as people have been saying for a long time presumably because of underpants gnomes. Now it could be that Trey and Matt would defend Keynesianism, increased regulation, and libertarianism all in the same breath. (Libertarians have also, unlike Rand Paul, defended federal enforcement of civil rights laws.) If so, I would listen to them intently, and I would welcome their argument as a pleasant shift in the political dialog. Then I would tell them that they were liberals.
* The title of this post is a play on a stupid book called "South Park Conservatives", in which some wingnut argues that Trey and Matt are anti-liberal, and that young, "hip" people are revolting against liberal media. The author does this in a shameless attempt to recruit young people, because everyone knows that Republicans are old and dying. I know very little about what Trey and Matt have said publicly about their politics, but people got the impression over time that they were libertarians. The "underpants gnomes" episode is clearly a defense of corporations against hippies, but the gnomes were not exactly convincing carriers of laissez-faire principles. After all, their economic model consisted of theft of underpants followed by an indeterminate path to profitability.
** Also, I can't help but draw parallels between the cult of Ayn Rand and the cult of Randy Marsh. To Randy Marsh and the Republican Party, poor people and poor people alone caused the recession by buying things they could not afford. (The economic tools that facilitated and expanded this profligacy are sacrosanct. Taking advantage of the poor is a God-given right.) To Ayn Rand, poor people were parasites. Their only function was to provide votes for Democrats. (The welfare as "vote-buying" meme.)
*** Here it should be said, because conservatives are hopelessly confused about this, that the Keynesian solution to recessions is not simply to print more money. Keynes realized that people need jobs in order to actually earn money, which is why the New Deal included employment opportunities. The government during the Great Depression invested the increased Treasury output toward useful projects like infrastructure and (eventually) defeating fascism. The money was not wasted, unless of course you like Hitler and you think that promoting the general Welfare is communist.
UPDATE: I was able to find two other critiques of the economics in "Margaritaville". They are both by libertarian authors. This one complains that Trey and Matt lazily set up Randy Marsh as a straw man. Randy, according to this libertarian, should have explained that the reason that people are profligate is government monetary policy (the artificial lowering of interest rates). Ok. Then what? If we went back to the gold standard then booms and busts would end? Bullshit. Who would determine the price of gold? God damnit, libertarians, the economy is people, the government is people, and soylent green is also people. What is so hard to understand? People set the price of gold, and they set the price of those pieces of paper with dead presidents on them. Elite people, whether they are in government or outside, will set prices. Liberals recognize that it is essential to have these price-fixers in the government. That way, the poor and middle classes have some leverage over them.
This author is much more reasonable.