Earlier quoted context omitted.
In general, banks do charge excessive fees on exchanging currencies. For example, if you want to exchange €1,000 to $ or £, they'll charge you (by default) a 2.5-5% conversion fee. After negotiating with them, you generally get it down to 0.3%. These days, I convert through my broker, because they only charge me 0.2% for FX conversions.
It's insane, borderline criminal. I knew someone who wanted to convert ~1m AUD -> USD -- and the banks were still trying to offer to do at 2-3% ! At that amount, you can open a brokerage account and trade through EBS or CNX directly and pay basis points.
You can open up a brokerage account at Interactive Brokers with a few thousand and use it to exchange FX. It's pretty accessible.