Come to think of it, I actually found a bootleg shop in Prague once!
If you walk out from the Muzeum tube station, you'll see that muzeum at the end of the broad road/place in front of you. If you take the bigger street to the right from that bigger placa you will find a record shop on the left, after about 200-300 meters. They had loads of Stones bootlegs two years ago! Can't describe it better, I'm sorry!
Belgrade-Bucharest-Budapest-Brno