Precisely that. The "price" of a dollar is what people are willing to buy it for. The "value" of a dollar is based on the extent to with people with a foreign currency are willing to purchase the goods/services produced by the nation issuing dollars, or invest in that nations assets. That's why when people tell me that the dollar is worthless because it's not backed by anything (usually uninformed people who think currencies should return to the gold standard), I retort that the dollar is backed by all the goods and services produced in the US. Basically as long as people are buying iPads, using windows computers, or advertising on Google, the dollar has a lot of value.
This is also why when the price of oil falls, generally nations whose expors are largely energy based fall as well. As in the case of Venezuela now, although they are trying to sustain an artificial dollar link. The "blue dollar" in Venezuela trades at 10x the official rate, way beyond what we see in Argentina (2x). It's also is a criminal offense to engage in the market so don't attempt to if for whatever reason you end up there.
Energy based nations that have smart economic policy, like Saudi Arabia or Norway, preserve huge amounts of the profits from their oil industry and invest it in massive globally diversified investment funds (referred to as sovereign wealth funds) in order to leave a legacy for future generations when the oil runs out, and to protect their economies from recessions caused by falling oil prices. Basically they have loads of money to spend when the economy looks bleak. Energy based economies that are poorly managed, ie Venezuela, squander all that income building a "socialist paradise" and then when the price of oil drops, fall into major crises.
Other poorly managed energy based economies (or would-be energy based economies), woo investors (ie Repsol in Spain buying YPF) to develop their oil fields, only to expropriate (or nationalise) Repsol's assets arguing that they underinvested in infrastructure. They then find themselves 2 years later with no energy infrastructure, no means to develop it domestically, no dollars to hire an external firm to do it, and no investors willing to take the risk of developing the infrastructure because it's a nation that has a habit of stealing all people's investments out of "national interest".
Just a comment on the Norwegians, their sovereign wealth fund is the single largest investment fund in the world. It's called Norgesbank. It's so big that they currently own approximately 2% of every company listed on European stock exchanges. The goal of the fund is to be able to reproduce the income stream of their oil resources forever once their oils runs dry, and to do so solely from the interest and dividends on their investments. All I can say is WOW! A Norwegian passport is worth it's weight in gold a thousand times over. I wish Canada had that policy...
Just another economic rant ;-P
Reneige