Money exchange:
If you decide to exchange money, it is best to do so in Prague rather than in your own country: exchange rates are always more favorable in the country where the currency is in use. Besides, on international foreign exchange markets, the Czech currency (as well as the currency of neighboring countries such as Poland, Slovakia, Hungary,...) is considered an exotic currency (currencies without real international value).
All foreign exchanges and banks in Prague usually calculate their exchange rate according to the previous day's average rate of the Czech crown as announced by the Czech National Bank.
You can exchange money in foreign exchange offices that you will find all over the city. They are usually open from 9am to 6pm, although some might be open later in the tourist locations.
CAUTION:
Not all offices work the same way and some are less honest than others: exchange rates displayed in large letters on office windows are often those for the ask price (what you have to pay in Czech crowns if you want the foreign currency in question) and not for the buying price, written in smaller print. You hence feel you will benefit from a good exchange rate, but the opposite is true.
Another common scam used by some offices is to display a sign saying there is no commission. The fact is that there is no commission if you buy foreign currencies, but if you are selling them you will have to pay for it.
Or it can be that in some offices, you don't have to pay a commission but that is only true starting from a certain amount, which is of course too high for regular clients (you will definitively not need 50,000CZK, about 1800€, during your stay :))
But lately in Prague, the foreign exchange market tends to stabilize (rates are also consolidating) and foreign exchange offices are becoming more reasonable (except in very touristic sites such as on Wenceslas Square, the Karlova street that leads to Charles Bridge, the Celetna street, the Old Town Square and near the Municipal House).
Where to exchange? Recommendations:
Exchange, at Kaprova 13 (same as our office :)) on the corner of the Kaprova and Maislova streets, mere steps from the Old Town Square.
No commission, good exchange rates, updated every day according to the rate given by the Czech National Bank.
You can also exchange money in banks, of which you will find numerous branches all over the city. Their opening hours are however more limited and restrictive than those of foreign exchange offices: they are usually open Monday to Friday from 9am to 5pm (sometimes until 6pm).
Banks might be less dishonest, but their system is not necessarily more advantageous: the used rates are often worse and some banks also charge a fee for their services.
Important advice:
Never exchange money in the street! It is the surest way of getting cheated and of finding yourself the owner of banknotes with no value or from a foreign country, such as Hungarian Forints, which value is 100 times lower than that of the Czech crown.
This tip is of course valid for all destinations and any trip, Prague is not the only place where this type of joke is being played on unsuspecting foreigners.
Money withdrawals and credit card payments:
In the Czech Republic just as anywhere else in Europe, you can pay for your purchase with a bank card (to the rate of that day and at no cost) if the store or restaurant in question is equipped with a secure card terminal. But other than in supermarkets, gas stations, big malls, high class stores and restaurants, this method of payment is not much supported.
As a rule, the old electro-mechanical card readers are not used anymore, and if you happen to be in a store where this system is still in use, the best to do is not to purchase anything there, so as to avoid having problems.
To withdraw cash at ATMs is certainly one of the best solutions to get Czech money (average rate of the given day) but with a fee: 30 CZK per transaction for withdrawals + the bank fee (the amount depends on your bank but is usually 3% of the total amount, with a minimum fee).
