The term "Good Old Days" brings back fond memories of digging out a stack of well-hidden Traveler's Cheques, and trudging to the nearest Banamex or Bancomer. Mexican banks always have long lines and you could count on waiting a half hour or more to cash the certificates for Mexican Pesos. Service hours to buy Pesos was always limited to just a few hours a day---this was because the Peso was just about always in jeopardy of devaluation against the US Dollar. Frequent federal holidays brought forth bank closure for the day. All-in-all going to the bank was tedious and very time consuming.
Today several dozen banks offer almost instant access to cash through thousands of Automatic Teller Machines located in just about every town that has a bank. If you want to know just how many banks offer ATM service, flip your FMT tourist card over and look at the bottom---there are a lot of different banks doing business in Mexico these days.
THE PESO
Mexican Pesos started with parity against the US Dollar at the beginning of the last century. A hundred and seven years later each 1900 Mexican peso is now worth 1/11,000th of an American Dollar. But the Peso today is in a relatively quiet period and worth 11 pesos to the dollar.
US Dollars are accepted in Mexico along the tourist border strip with the USA and in most of Baja California and Baja California Sur. Outside of these areas the dollar is not accepted in trade except at five-star hotels. These places tend to warp the heck out of the proper exchange rate, and give the customer eighty cents worth of purchasing power for every dollar spent.
It is best for RV'ers to use an ATM card to purchase pesos at the first overnight stop in Mexico. You will need to check with your bank to see if your ATM card can be used in Mexico. A four-number PIN is required in Mexico.
TRAVELER'S CHEQUES
Having enough Traveler's Cheques to at least get back to the USA would be an extra prudent idea. An ATM machine "could" swallow your ATM card. Or you could lose it. The magnetic strip on the back "could" get damaged. Or your bank could suddenly hiccup and leave you stranded. None of these options are very likely of course. If you retain the copies from your travelers cheques in a safe place, even lost cheques can be replaced.
CREDIT CARDS
Cash advances against credit cards are expensive. And purchases are difficult to monitor if you fail to keep in tight contact with your bank. For those reasons and the possibility of fraudulent purchases, I relegate CC'ds to the bottom of the heap when it comes to selection of alternative backup plans for emergencies.
ATM CARDS
This is the way-to-go and especially so if you have established an online bank account that can be monitored from any internet cafe in Mexico. ATM transactions ALWAYS give a much better peso exchange rate than credit cards, traveller's cheques, or dollars for pesos. Machines that swallow cards are very rare. I keep my card in a paper sleeve provided by my bank. Now if I could only find a US bank that had online account management coupled with FREE ATM transactions... Hint: Decide before you depart as to how much money you want to set as a daily limit on your ATM transactions. Five hundred dollars seems about right for most folks.
CURRENCY EXCHANGE FEES
A couple of years ago I had a pair of tires on my rig fail when I was just about across the street from a tire distributor. I purchased and paid the equivalent of four hundred dollars for a new pair of tires. I used a VISA ATM card to pay for the purchase. Along came my bill online and I was shocked to see a fifty three dollar "Currency Exchange Fee" tacked on. Extracting five hundred dollars cash from an ATM machine would have only cost ten dollars total. Now I use the card solely for buying pesos. I wish I could charge my US bank ten dollars per transaction (because I feel that my business is worth that much :-)
PESO POWER
Peso currency comes in the following denominations: Twenty, Fifty, Hundred, Two Hundred, Five Hundred and One Thousand pesos.
Coins are available in fifty-centavos, one, two, five, ten, twenty, fifty, and one-hundred pesos. Except for the fifty centavos piece ALL MEXICAN COINS ARE OF Bi-Metal CONSTRUCTION---a bonding of silver plus brass colors. If you ever get presented with a large coin that is of a single metal (Except for the brass 50 centavos) it is valueless. Trading in tiny twenty centavos and ten centavos coins does happen on occasion but only rarely. The miniscule silvery slugs are legal tender but seldom used.
Bills that are torn, taped, smudged, stained, or otherwise worn are commonly refused by merchants. So, if you are offered such a bill in change, refuse it. A gas station is a good place to try and discard a defaced peso note.
Ten peso notes were pulled from circulation several years ago and are worthless today. Twenty peso banknotes are now made out of a plastic material and feel slick. Paper 20 peso notes are worthless. Twenty and Fifty peso banknotes are about an inch shorter than more valuable banknotes.
All obsolete Mexican coins and bills are absolutely worthless today. Even bills depicting "NEW" Pesos are worthless. Spend a moment in camp with a helpful neighbor and they undoubtedly will offer further advice about Mexican monies. Most banks have helpful currency charts posted on the wall.