Questions re money and move to Lake Chapala

I am concerned about working out the money situation there for 3-4 months.  I had told my bank that I was going on a Mexican trip so as to be able to use ATM to withdraw money.  Didn't happen.  ATM outside WalMart didn't take my card.  It didn't recognize my debit card.  Called bank, got no where.  Had to borrow from tour operator.  Don't want problems this time.  Any thoughts on how to be certain of accessing my money?

Also, how much Mexican currency should I take for the drive down in spring?  What denominations would be best?  Several hundred dollars is a lot of paper in pesos!

Your card will be recognized if you follow the network affiliation noted on the back of your card and the networks supported by the ATM. Those networks will be displayed next to or above the ATM. Crisp 100 dollar bills with no markings in ink nor any tears, i.e., perfect. Next job will be finding someone to accept them and exchange them for pesos. Best bet would be a money changer as banks are shying away from exchanging any currency.

When were in Oaxaca, we had no trouble using an ATM that was attached to a bank.  I do not know if that is any help.

I use a Bank of America ATM card at banks in Mexico.  Walmarts usually have multiple bank ATM's inside.  As someone else noted look for network symbols to match your card.

I don't think cash is a good option.  ATM machines give you a better rate. If you don't carry a balance, credit card purchases may give you as good a rate as the ATM.  Money exchanges take a pretty hefty commission; businesses even heftier.