In an effort to stem the flow of illegal cash funds passing through Mexican banks and businesses, Mexico introduced a series of measures to limit the amount of foreign currency that companies and individuals, including tourists, may deposit into banks, exchange into pesos, or pay for goods at stores using US dollars in cash.
The measures are not intended to affect tourists, and even foreigners living in Mexico are not likely to be affected by the new regulations, which limit the amounts of US dollars in cash that may be deposited or exchanged at banks, but do not affect any electronic transactions—including bank wires and ATM withdrawals—as, unlike cash, these are traceable to their source.
One of the policies which could affect some tourists is a new regulation that limits the amount of cash that can be used to pay for purchases at a store when paying in U.S. dollars. When the regulations were introduced in June 2010, this limit was set at US$100. Earlier this week, the limit was lifted to US$250 per transaction for stores situated in the country’s principal tourist areas and the Baja California peninsula.
To be clear, this limit only applies when you are purchasing items from a store using US dollars in cash. If you pay using Mexican pesos in cash, or a credit or debit card, there is no limit to the amount you can spend at a store in any transaction.
See Also: Guide to Money in Mexico