The falling value of the dollar is a common topic—and not just in economic or political circles. Whether your grandma tells you what she used to be able to buy for a nickel, or you reflect on how cheap your rent was five or 10 years ago, concerns about what a dollar buys these days are becoming as common as dollars, what with how many of them the Federal Reserve seems to be printing these days.
In spite of this, the U.S. dollar remains a relatively valuable currency, especially compared to these.
Iran has been one of the biggest travel stories of the past few years, a trend that's almost certain to continue into the future, whether certain world leaders like it or not. Unfortunately, barring some action by the country's parliament to re-denominate its currency, the Iranian rial is likely to remain a poor performer, even as the country's tourism stock rises. As of writing, the Iranian rial trades at about 42,600 to one US dollar, although money changers on the street will usually give you a bit more than that when presented with crisp, new $100 notes.
In addition to being one of the world's most worthless currencies, the Iranian rial is also one of its most confusing. Locals often quote prices in toman, which is simply an Iranian rial with one zero removed. The end result is numbers that are still too high for sanity—7,000 of any currency for a cup of coffee boggles the mind.
Vietnam's currency is worth slightly more than Iran's, with each US dollar buying you about 22,900 dong as of June 2018. One important difference between these currencies—between the countries, really—is that Vietnam's banking system is connected to the rest of the world's, unlike Iran's. This means that you can become a millionaire instantly by withdrawing currency from a Vietnamese ATM. Specifically, withdrawing $50 worth of dong (1,133,425 dong) will make you a millionaire, at least as far as Vietnamese money is concerned.
While Vietnamese notes as small as 500 dong (2 cents) used to circulate, the smallest Vietnamese bill you can officially get these days is 10,000 dong, which is worth a little less than 50 cents.
Another Asian country with a relatively worthless currency is Indonesia. Although Indonesia is rapidly developing, leading to quickly rising costs in tourism hot spots like Bali and Yogyakarta, the rupiah still remains one of the world's weakest currencies. Currently, the USD-IDR exchange rate is about 14,200, which means that you could end up dropping six figures for your next Indonesian lunch.
Indonesia is an increasingly tech-friendly country, however, which means that you won't have to use cash all the time, as you often do in Iran and Vietnam. More and more merchants are accepting credit cards, while the introduction of Uber in many major cities not only means an end to haggling about prices for transportation, but eliminates the chances that you'll be scammed due to miscounting your extremely big bills.
Just because a currency is worthless doesn't mean it's cheap to travel in the country it's used for. For example, while the Laotian kip is significantly less valuable than the baht of its neighbor Thailand (1 USD=8390 LAK, while 1 USD=33 THB), many travelers find prices in Laos higher, in spite of Laos being a markedly poorer country than Thailand.
Of course, there's a secondary reason for this. Due to the low value of the kip, Laos' economy is partially "dollarized," meaning that prices are often given in dollars and dollars are frequently accepted for payment.
In addition to the fact that Paraguay's landlocked between significantly more popular countries (although you can visit the famous Iguazu Falls via Paraguay, almost every traveler goes through Argentina or Brazil), the Paraguayan guarani is one of the world's most worthless currencies. Specifically, each trades at about 5,700 to the dollar, which means that in spite of bootlegged electronics in Ciudad del Este being cheap, you'll have to shell out hundreds of thousands (or even millions!) of guarani in order to be able to buy them.
Another nearly worthless currency in South America is that of Colombia. To be sure, while the Colombian peso is worth slightly more than the guarani—$1 exchanges for around 2,900 Colombian pesos, making it around twice as valuable as the Paraguyan guarani—tourists are simply likelier to visit Colombia than they are to visit Paraguay, what with world-class destinations like Cartagena, Medellín, and the Coffee Triangle.
A fun fact about pesos is that they're the currency of a large number of Latin American countries, including Argentina and Mexico. A less fun fact is that they all have different exchange rates, so familiarize yourself with the exchange rate of the peso you'll be using to avoid getting hosed.
Another poor-ish country with a worthless currency that still manages to be rather expensive is Tanzania, whose shilling equals a dollar only when you have 2,275 of them. Then again, if you've ever traveled in sub-Saharan Africa (one of the world's most expensive and lowest-value places to travel, in spite of the poverty most locals experience), this won't surprise you.
To be sure, what might come as a greater surprise (or, at least, a valuable insight) is why so many African countries are expensive, whether or not theirs are among the world's most worthless currencies. The problem is two-fold.
Since many African countries don't have middle classes, the travel industry remains likewise split between extremely high luxury and extremely low budget—you can travel like a local, as long as you don't mind waiting hours or even days for a cramped bus that's likely to break down.
The second reason Africa is an expensive travel destination is that within the travel industry, there isn't a lot of competition. Many of the most popular safari destinations have only a few companies operating tours, while even large cities like Nairobi have so few luxury hotels than none are forced to compete for your business.