Which currencies will the SUSECON Store accept during the event?

I ask because I received a tip to take and pay for things in Czech Koruna rather than Euros, UK Pounds, or US Dollars as the conversion rate used is (predictably) more favourable to the Czechs than visitors.

Presumably the Store will accept payment by credit card as well as cash though it would be useful to know which currency that will be charged in - I'm guessing US Dollars, Euros, or Czech Koruna?