I think that I've found probably "the best" Exchange Office in Prague. The best rates both for buying CZK and EUR, USD, GBP. PRAHA EXCHAGE Jindriska 12, Praha 1. (Between Hlavni posta/The Main Post Office and Vaclavske namesti). Open : MO-SU 9.00-22.00 www.prahaexchange.cz Anybody knows a better place?
Impresive, they are selling USD for 0,10 CZK less then the best place I know. However I have never heard about this place, but will try.