Since Prague is still not part of the EU, you must change your currency at some point. By far the best deal is using an ATM machine. There are two at the airport, not far from the information desk (who can point it out to you). When I went to use one, there was a uniformed armed guard carrying an automatic weapon who I had to shoo away (very carefully!). I recommend you take out a minimum of 1000 crowns (35 euros), but not more than 3000 (100 euros) at a time. If you plan to pay for hotel and meals with credit cards, that should be plenty of cash to play with for a couple of days. You’ll spend less in Prague than you’d expect to spend elsewhere. There are ATMs in town at most bank branches. If you can’t use an ATM for some reason, banks offer the second best exchange rate for cash or traveler’s checks. Of course when they’re closed you won’t have that option.
You can also change money at the many currency exchange windows in town, but they will, without a doubt, give you much less by adding commissions and poor exchange rates. Don’t believe it when they say no commission. That is only if you are trading in Czech crowns for other currencies. You could easily pay 10% or more for a small transaction.
You may also be approached on the street by unscrupulous people who want to change money for you. Don’t do it, or you’ll surely be ripped off! They often try to sell you old notes that aren’t accepted anymore. You’ve been warned!
Once the Czech Republic enters the EU, Euros will rule the day in Prague. But like other countries who went the Euro route, you can expect prices to jump big time when they convert their crowns to Euros. So enjoy the Czech bargains while they last!