What Gives a Dollar Bill Its Value? is a nice TED-Ed lesson on the influence of the United States Federal Reserve banks on the value of currency. The lesson includes a short piece about the correlation between inflation and the overall health of the U.S. economy. The lesson is probably best suited to high school students who already have a basic understanding of how the value of currency is determined.
What Is Money? from The Atlantic's series on economics is a good complementary video to What Gives a Dollar Bill Its Value? What Is Money? uses the fun scenario of trying to deposit a banana into a bank to explain the basic purpose and function of money. The video is embedded below.