I have been busking for about 10 yeas now. Started in Winnipeg Canada. I had a career, making good money until one day i decided to busk outside of a liquor store. I made 450 bucks. What a day. I quit my job after that and started travelling and busking full time. I know alot of good and bad places to play.
For the last year I have been going around Europe. Germany is my favorite place although alot of towns and cities you need a permit. I actually had my guitar confiscated by the cops in Bernkastel-kues because I didnt have a permit or the 20 euros for the fine. (i had 19 euros. they wouldnt accept that and even 2 different guys who were listening offered to pay but the cop said no.)
I have been in Prague for a month now. Absolutely the WORST place. It is illegal to busk, you need to go through 5 different offices to finally get a permit which costs about 2000 Czech crowns (about 80 euros) AND chances are they dont speak any english. also, its a poor place. lots of foolish tourists, sure, but also WAY too many homeless and drug dealers and neo-nazis. Its funny how I cant even finish tuning my guitar outside before a cop or security starts babbling to me in Czech to get lost. But they dont really care about the drug dealers. If you plan to go to Prague and busk, change your plans. I tried everything.