We are entering the summer here in Canada (northern hemisphere to be correct) and it is the main travel season for many people. This travel is often far overseas, as much of the charter aircraft used for Caribbean travel are shifted instead to Europe. So you are headed overseas and need a few hundred dollars worth of foreign cash? Many people don't feel comfortable travelling without having some foreign cash on them. This is a prudent move, as you may have problems finding an atm that works with your bank card upon landing in the distant land. And then there are the service charges. Ten years ago I used bank machines in places such as Poland and Austria, and was only charged $2.20 per PLUS system transaction. Today, that same transaction will probably cost you between $5 and $10 dollars just in transaction fees. So much for technology making things cheaper. But of course these transaction costs are simply a bank gouge. They also get you on the exchange rates although those rates are usually pretty decent.
If you decide to bring a lot of foreign cash with you, please consider going to a foreign exchange place instead of your bank. Here in Ottawa we have Accu-Rate. They fairly consistently beat the bank exchange rates, and you can pay with your bank card as an interac direct payment. By going there, you can easily save $10-$20 or more depending on what you're buying and how much. Also, the foreign exchange place is likely to have the foreign notes that you're looking for. The banks only carry a small selection and it is not uncommon for small branches to run out of the popular currencies such as Euros.
To somerize, all I'm trying to say is do shop around a bit, as most of these places including the banks do post their rates and update them throughout the day. If you spend 20 minutes online and find a $20 saving, then your time was well spent at $60 per hour, as long as you don't have to drive a long way to the establishment. Also ask your friends and coworkers if they have any favourite place to exchange money. Sometimes friends have some foreign cash that they haven't exchanged yet and are willing to give you a good deal. You can both win on such transactions as the buy/sell spread is usually a few percent.