What things cost in Denmark

[Carotio]

You can pay with Euro bills, no coins, in many places, but usually at a bad exchange rate.
You better have credit cards like VISA, MasterCard, American Express, Diners, VISA electron and EC/Maestro.
And you should definitely have some of your own money exchanged into Danish currency. I'm not really aware, where you can get the best exchange rate. I have a 6th sence telling me that the worst place to do it, is in the airport. There is a small cash exchange office just next to the place, where you'll be waiting for your luggage to arrive. Sorry, but I did not think about to have a look, when I was there a few weeks back, at what prices they had. But it's an option...
Or maybe you can do it in a bank in your own country...