Usually the highest rate in the area (that doesn't charge a commission or exchange fee). When I was…read morehere the rates were higher than those closer to the border - BUT they also constantly change, so they may or may not be the same as other ABC Money Exchanges at other locations. Sometimes, for very short periods, one or more of the nearby money exchanges might have a slightly higher rate, but in a few minutes, as soon as the rates change again, this place seems to consistently have the best rate to buy MXN Pesos (and often the lowest spread or difference between the rates to buy or sell).
Since the rates seem to constantly fluctuate, if you have time, and the rate is less than it just was or that you saw somewhere else, or had thought and hoped it would be, wait around a little, and then buy when it changes back (closer or possibly at an even better rate of exchange).
Nobody can really predict when is the best time of the year, month, week, or day to exchange money, but given the daily timing of both Mexican and U.S. "economic releases" (8:30, 9:00, 10:00, and 10:30 am Eastern Time), the best time to buy or sell Mexican Pesos locally MIGHT be a little before or after 11:30am, 12:00pm, 1:00pm, 1:30pm Pacific Time - and POSSIBLY on a Wednesday or Thursday afternoon (but not necessarily and I have no evidence to support this recommendation other than one clerk's guess when I asked).
If you have a no foreign transaction fee credit card, charging purchases while traveling is SOMETIMES a good way to not only delay payment, have some "protection" in case you need to dispute a charge, but also end up paying less than cash (depending on when the purchase/charge posts and what bank the card is from and the exchange rate they use at the time). Either way, it's always good to have some cash on hand since not everyone accepts credit (or charges a fee or has to include taxes or something else that they don't when paid in cash) - and it's also usually helpful to already have at least a little local foreign currency before leaving the U.S./traveling/crossing the border - as it is even more unpredictable when and where and for how much and how "safely" you might be able to exchange money later/in country. Most but not all people and places will probably accept U.S. Dollars but paying in Pesos is usually cheaper (especially if they ask for Dollars) BUT you have to keep in mind the rate you BOUGHT your Pesos rather than whatever the exchange/conversion rate being used at the time might be to see which currency would get you the most for what you agree to pay. Prices are often also "negotiable" - so assume a better price may be possible IF you are willing to ask for it.
This is the fourth or fifth ABC Money Exchange I've been to and while they are far from the only place to buy Mexican Pesos in San Ysidro or Otay Mesa, each location, including this one, has been a good, quick, no hassle, experience - and so probably the chain I would most recommend (with Baja-Mex next - both for money exchange and car insurance).
This building is almost at the corner. Parking is free on both streets - and they also have a small lot for customer parking at each end of the building. Not all clerks speak English but you shouldn't have any problem if you don't speak Spanish.
