I suppose if you cash a piddling $100 at a time then the transaction fee will assume more importance. But really, the transaction fee should be of no consequence whatsoever since you should not be using a bank that charges ANY transaction fee at all. There are plenty that don't even in the USA. So you should only have the exchange cost to worry about since it is much harder to find a financial institution that charges no exchange fee at all unless you live in the UK and can open a Nationwide account.
Accounts like the one described by germuno which require you to maintain a certain balance may be available in your part of the USA Nicole or Credit Unions are often a good place to look for low exchange fees.
By the way Germuno, as you are probably aware, some US banks either ignore or are given permission to ignore the Visa ban on charging an ATM fee on foreign card withdrawals. Well little Borrego Springs Bank with only 3 branches charges no ATM user fee on my Canadian or UK cards while the Wells Fargo ATM in town charges $3 on those same cards. Tells me a lot about Wells Fargo.

