I suppose they can charge whatever they want to charge, since such fees aren't regulated.
However, I was in banking back in the days before ATM's (anybody remember?) and I recall the arguments the banks all posed to the regulators, as they lobbied for approval to start putting machines on every street corner.
The presented ATM's as a win-win situation, whereby (1)the consumer could have 24/7 access to certain banking services, and (2)electronic transactions were much cheaper for the bank to process than transactions in a branch. As business migrated to the ATM's, the banks would need fewer branches and could reduce personnel...another savings to the bank. So, the regulators agreed and the banks went crazy.
Then, the banks saw an opportunity for some fee income, so they went back to the regulators and asked for permission to charge a fee. In fact, the bankers were very persistent, and said that unless they could charge fees, they couldn't afford to install additional machines!
Of course nobody recalled the original argument...that the banks wanted ATM's in the first place BECAUSE THEY SAVED MONEY!. And nobody opposed the banks by simply suggesting that if they can't afford to install more machines, perhaps they shouldn't.
Anyway, the regulators caved-in, and here we are today with $3 ATM fees.
Higher ATM fees usually do not generate the incremental revenue they appear to at first blush, as they encourage folks to access cash in less costly (although frequently less convenient) ways, or make larger average withdrawals. Demand elasticity in action.
Being long BAC, I happen to like the move.
Don't like paying the three bucks - use another machine!