Apparently, the Travelex Company (the World's Foreign Exchange Company, according to their website) worked out how much things would cost in Euros to attend Harry Potter's fictional Hogwarts wizarding school. One of those nice broomsticks will set you back over 2k, and a wand around 50 euros. The "exchange rate" for a gold galleon is approximately 7.40 euros.
In fact, they claimed this was a unique experience for them since it was the first time they worked out the value of a fictional currency, which is said to be really sturdy and could assert itself on the international money market.
It is nice to know that a fictional currency would do well on the market. Too bad some real currencies aren't faring as well.