I'll go ahead and put in my vote for Rio.. I live here...
The whore scence starts at $R1 per minute (about 40 cents) and goes up to $R500 for all night, with every other price available in between.
Don't forget the world famous Help Disco... Everynight about a 7 to 1 whore to guy ratio with prices starting at about 40 bucks.
check this site for the every little bit of information about the scene in Rio..
www.clubhombre.com