Where to buy pesos

Thanks briansue. The cajero automticas reference is the perfect source to find ATMs. It can be used all over Mexico. We generally stay over night at the truck stop in Eagle Pass and then in the morning go down Main St. to S Monroe St. and follow it around to the bridge into Mexico. There are banks just off of Mirador St.in Piedras Negras that we didn't know about. Thanks, it will be easy to get pesos from the cajero automaticas there.

I am only familiar with Laredo but there are competitive private exchange businesses that buy and sell pesos at fair rates. Once in Mexico I buy Pesos at ATMs with a credit union debit card.
Just be sure to tell your card provider that you will be using the card in Mexico or they'll suspect fraud and shut it off.

Do a Google search using Piedras Negras Cajero Automaticos (hightlight and right click here) and you will see locations of ATMs in Piedras Negras on a Google Map. There appears to be a Bancomer and a Santander within blocks of the border. ATMs almost always give the best rates. The Google search will turn up others. We prefer to use machines at banks where they usually have the lowest fees and if something goes wrong you can go in the bank to discuss any problems.

Casas de Cambio sell pesos at a much better rate than banks. Outside all aduanas you'll find drive thru places; Laredo, Reynosa, Anzalduas, Matamoros, Pharr, etc.

The rate banks in the US give is horrible. How horrible? Last time I checked, it was 30% less than the going rate. That's serious. They also had a large minimum purchase requirement.

Other options? Near the border there should be numerous visible places to buy and sell pesos and dollars that will give reasonable rates. Reasonable enough to be worth the minor hassle of finding them. Buy enough to get you to an ATM-they are plentiful and have the best rate available.

Remember when you leave the country to keep enough pesos to get you to an ATM next trip down.

Besides, how many pesos do you need right away? Practically all PEMEX now take credit cards.

almost all banks will sell Pesos...I bought mine at my Wells Fargo, and they gave me full refund on those I didn't use