I would advise against bringing traveler's checques to anywhere in central and eastern Europe. You simply will not get as good an exchange rate as you will with cash. Your best bet is to probably open a bank account at home that doesn't charge fees for using a foreign currency ATM, and taking the money out that way. Banks will usually give you the best exchange rate of the day.
if you do change your money at the licensed dealers PLEASE PLEASE be sure to read the fine print ....all the dealers advertise signs that say 0% commission!!! this is a load of bull......there is also fine print at the bottom saying only for selling purposes....that means when u exchange they can take a commission rate up to 10% which is a downright rip off....please be very careful ...ASK how much commision is charged before you hand over the money (even if the sign says 0%) because they will not return the money to you once the exchange has been made.
If you need to change money, don't do it at the airport or at your hotel - they give you the worst rate ever. Always compare the rates between the different change booths. Don't be tempted by the signs saying '0%' or 'No commission' - always ask how much you'll get for US$100 (for example). One very reliable change booth, which gives you a fair rate, is located near the Old Town's square: when you are there facing the astrological clock, you'll see to your right, accross the square, to streets; the booth is located in the rightmost one, on it's left side, just around the corner.
Change money on the street: You may realize a better rate than that available in a Forex Office! My friend Rick tfaded US dollars for korona, and got 1000's of old Polish Zlotys in return. Although almost totally worthless it makes a great story
In Prague we were scammed. The exchange office is dishonest. Be careful not to use the OFFICE change Western Union. Always ask the exchange rate before giving money.
Change your money only at banks , the course is better .
Don´t change money on the street !!!
Take care of your valuables !!!