Bank of Ayudhya ATM's appear not to be free of charges
We were in Bangkok about three weeks ago and always used the Bank of Ayudhya ATM's b/c they seemed to be the only ones that did not mention the 150 baht charge. They have bright yellow signage and are included in the ATM bank at the airport public transport center, and are all over Bangkok.
I can't confirm the exchange rate or that the charge hasn't appeared yet since my boyfriend made all the withdrawals