Unlike Argentina's, Brazil's culture is not U$S centered. In Argentina, prices do not match exactly currency exchange fluctuations, but if the dollar goes up, local prices follow. All prices, not only sex workers' fees. Besides, talking specifically about prostitution, as there is not a public market like Brazilian saunas, there are differentiated fees for local and foreign clients.
Not in Brazil. However, I noticed that many Americans think that GPs are quoting them a different fee because they are Gringos. I think this misconception could be coming from not understanding a bargaining culture.
In a Brazilian sauna, a GP will always quote a high price first to a new client, whatever your passport is. It is up to your mastering of the game to pay the price you want. I usually negotiate a price that is about 50 Rials above what local clients pay, but I could easily negotiate a lower price. Part of this negotiation is establishing empathy and connection. A likable potential client get better deals.
Your nationality has really no weight in the price you pay in a sauna. If you do not know the game, you will overpay whether you are a local or a visitor.