Astronomical Exchange Rate

Sometimes economies in fiction just don't make sense. Enough money in one country to buy a hot dog will buy you a plane in another simply because one currency is just that much more valuable than the other.

Perhaps the other culture has a very stable and powerful economy. Perhaps they have certain elements in abundance. In any case, we are not talking about Worthless Yellow Rocks or Solid Gold Poop (at least most of the time), it's real money on both sides. However, if you can buy a house for your country's price of a meal...

Film

 * In Eurotrip, the gang find themselves in a poor part of Slovakia with only $1.83 among them. It's enough money to get them the Presidential suite at the nicest hotel in town, with several feasts.
 * Apparently, 5 cents is enough to open a new hotel.

Literature

 * Twoflower's gold in Discworld. A few weeks salary on the Counterweight Continent is enough to buy the entirety of Ankh-Morpork several times over.
 * This is really just the fact that the Counterweight Continent happens to mint money with Worthless Yellow Rocks. There's no real trade between them and Ankh-Morpork, which would be required for this trope to really work. That said, this trope is the reason there's no trade between them.
 * Phrased by Vetinari as, "We have nothing they want, and they have nothing we can afford."
 * In the Second Foundation, there is a scene where a teenager girl gets 10 Foundation credits as pocket money. When she exchanges it for local currency, she gets a "terribly thick sheaf". It was enough for a long shopping spree, which included a dozen dresses and a complete makeover.
 * In The Stainless Steel Rat, the Space League does this to less advanced worlds. At one point, the protagonist remarks that this is the way he would have programmed it, and he is an interstellar scale crook.

Video Games

 * Played with in Mario & Luigi: Superstar Saga. The exchange rate starts out at about 100 Mushroom Coins=10 Beanbean Coins, but near the end of the game, you win a bet for 100 trillion Mushroom coins... and learn that in Beanbean coins, which is all you can spend in the game, this amounts to... 99. The Mario brothers, they cannot win!
 * That's right, Peach is such a crappy ruler, that it took less than an entire game for the exchange rate to skyrocket to the point where the Mushroom Kingdom would be better off starting over economically.
 * Maybe if Peach didn't spend so much time installing racing circuits and tennis courts all over her castle...
 * At least she doesn't waste money on her defense budget. The only defense the country has is 'ask Mario to rescue me, then give him a peck as reward'.
 * Well, Mushroom Kingdom had an army, but it didn't work out. It turns out that Goombas were soldiers for the Mushroom Kingdom, but they defected to Bowser.
 * In the setting for EVE Online, one ISK (the in-game currency) is said to be enough to retire to any planet and live like a king for the rest of your life. That said, living in space is essentially living like a GOD, what with the immortality and all.
 * Get's pretty ridiculous when you buy things for billions upon billions of ISK. That's entire economies that you could crash. With a fraction of that.
 * Note that this is an Informed Ability that doesn't really work when you try to translate it to the prices of stuff in the game. 1000 bullets for your ship's machine gun selling for an entire planet's GDP? Don't think about it too hard...

Western Animation
"Guard: You'll have to leave now, sir. The museum's closing. Homer: Perhaps an American dollar will change your mind? Guard: U.S. currency! What time would you like your breakfast?"
 * In the Family Guy episode "Jungle Love" (The One With Chris running away to join the Peace Corps in South America) when the family come after Chris, Peter becomes the richest man in the country, with US$37.
 * In The Simpsons "Treehouse of Horror II", Homer is caught smuggling a huge amount of illegal items and is charged a fine of two american dollars.
 * In another episode, Homer uses this to bribe a museum guard in Canada.

Real Life

 * Doesn't really work this way in real life. A dollar is worth around a thousand Franc Congolais, and this helps travellers going to Congo with their food budget, but the actual worth of stuff doesn't vary that greatly. And even if it does, it'll be mostly due to lack of shipping costs.
 * It might even turn out to be worth less in the local currency (depending on where you are) because of the extra money needed for American standbys, like clean drinking water, beds without bugs, food that's safe to eat, and reliable transportation.
 * The difference in living standards is a far greater problem than actual cost of goods, and breeds crime like nothing else. If an official of the Third World countries can be bribed with a few dollars, the price of a McDonald's' meal, how easy would it be to do whatever you want, with no fear of reprisals?
 * Real life currency tends to be far more valuable than the currency in MMOs. As in, one U.S. dollar is often worth a few billion of the in-game currency. Four U.S. dollars will net you about 1000 gold in World of Warcraft.
 * Examples of this can happen when a country creates or relaunches a currency. In 1945-46, Hungary experienced hyperinflation on an epic scale. At its worst, prices were doubling every 15 hours. In the end, the government issued a new currency (the forint) to replace the dying one (the pengő). The exchange rate was a sickening 400 octillion pengő to every forint. That's a 4 followed by 23 zeros. This is literally astronomical. Every single pengő note in existence, combined, would not have been enough to exchange for 1/10 of a forint. The pengő wages you had earned in previous years, your whole life's savings, were instantly worthless.
 * A more recent example would be the hyperinflation in Zimbabwe from 2007 til 2009. At its peak, the exchange rate from Zimbabwe dollars to US dollars was roughly 10^30.