Upvote:4
Any kind of currency transaction that involves (a) cash and (b) a human being handling that cash is going to incur charges of at least 15-20%, which is pretty much what it takes to keep that person employed and sitting behind a desk with some safes and secure glass and all that nonsense, not to mention the cost of moving big piles of cash securely around between countries.
So when possible, never use (a) cash or (b) humans. In general I try to use ATMs to withdraw money from my own checking account in the destination country. There may be a 2-3% fee for doing so but this is dramatically less than the fee for going up to a money changer.