To be "ripped off" by kantors or shops is an art that has been carefully developed in order to pick up customers who are cavalier about the price just as the customer presented in the OP:
Visit the closest bureau. Foolishly don't check the exchange rates (...I travel all the time so I should know better)
The strategies for "price targeting" techniques are excellently described in a book by Tim Harford, "The Undercover Economist", from which I am quoting this passage:
I once spotted a particularly inspired trick while on a search for crisps. My favorite brand was available on the top shelf in salt and pepper flavour and on the bottom shelf, just a feew feet away, in other flavours, all the same size. The top-shelf crisps cost 25 per cent more, and customers who reached for the top shelf demonstrated that they hadn't made a price-comparison between the two near-identical products in near identical locations. They were more interested in snacking.And another one, as well from the US:
Amazon used to tailor their prices based on their records of individual customers. The company really was able to offer "money on" vouchers: two customers buing exactly the same product would be offered different prices based on what, if anything, they had previously bought. [...] Customers started to realize that if they deleted the cookies on their computers, they were offered different, often lower prices. And when they found out what the company was doing, there was an outcry. Like Costa [the coffee bars chain described earlier in the book]
, Amazon has promised not to do it any more.