Thank you both. I would be using a US based ATM/debit card. Some of the online stock brokerage sites in the US provide debit cards (Ameritrade, E*Trade, Fidelity, Charles Schawb). And you need not trade stocks with these brokers. You could just put money into an account with them like a bank and get the benefit of their versatile debit cards. All these brokers also have no minimum balances. So you could keep a $0 balance and just put money in when you want to travel with an ATM/debit card.
All 4 of those, for the exception of ETrade, don't add any charges on overseas ATM withdrawals, which is great (ETrade adds 1%) and even Fidelity and Schwab will refund your ATM withdrawal fees if there are any from overseas banks.
Unfortunately I don't have either of those, but Schwab is the absolute best because no fees at all on anything and they refund any overseas ATM charges as I said. Fidelity though would charge 1% if you used their debit card to make a debit purchase, whereas Schwab doesn't have any fees on debit purchases either.
Ranking them in terms of charges, Schwab #1, Ameritrade #2 (has no charges at all on ATM or debit card purchases but doesn't refund any overseas ATM fees), Fidelity #3 (charges 1% on debit purchases, but will refund ATM carges charged by an overseas bank) and ETrade #4 because they add 1% to everything and no refund on ATM charges either.
They are still better than a US bank like Chase for example, which told me they will add 1% to the ATM withdrawal amount, plus add another $5 charge and they wont refund the overseas ATM fee charges either. You can't get worse than that!
Anyway, very sorry, I went off on a bit of a tangent there.
I was thinking about using one of the 4 big banks like Bankia, BBVA, Caixabank, or Santander for ATM withdrawals, which I assume I can find in all cities I will be visiting like Valencia, Granada, Cordoba, Sevilla, and of course Barcelona.
It sounds like I should avoid Ciaxa though it sounds like. But if I am charged a 4-5 Euro withdrawal fee, which my bank wont reimburse, but wont charge me anything on top of either, then it is fine. I may make only 5 withdrawals while I am there. So I think I can live with those kind of charges for those few withdrawals I will be making, as long as the fee isn't a percentage.
Well, it sounds like the thing to do is stick your card in a few different major bank ATM machines and see which one will charge the least or nothing at all perhaps. Sounds like even the banks themselves change their fees depending on location and I guess that is why I got conflicting reports from other sources.