As one who still "works" for simMarket - I had to go look see.
The currency tool is in the nav bar on the left. Scroll down and you will see a "Currencies" drop down selection window. Note the "caveat" about purchases being made in Euros - the conversion rate from the simMarket "bank" at the day and time of the transaction MAY be slightly different.
By "working" I merely mean that I am forum Admin and keep an eye on things there with a couple of other guys.