Currency exchange shops around Old Town advertising "No Commission" are total scams. They give rates 20-30% worse than banks, plus hidden fees in fine print. Street exchangers near tourist spots even worse — Many give counterfeit bills.

Use ATMs inside actual bank branches only. KB (Komerční Banka) and ČSOB branches throughout Prague offer fair rates. Avoid Euronet ATMs (ridiculous fees). When paying by card, always choose Czech crowns (CZK), never home currency conversion — Adds 5-8% markup. Bank ATMs typically charge reasonable fees vs 200-300 CZK loss per 1000 exchanged at tourist shops.

Exact comparison: 1000 CZK from bank ATM costs ~€41. Same from Old Town exchange shop costs ~€53. That's €12 loss on small amount.