There are new ways to bring money into Mexico. If you cash a check at a local Bank, their exchange rate costs you approximately 7.5 % of each dollar you import. ($350 dollars for $5000 imported.) I noticed the exchange rate for one bank was 17.13 vs the listed rate of 18.53 Using an ATM costs me about 2 1/2 percent.
There are now companies that cut out the middle man and save you a lot. The company I used is TransferWise, Inc. They give you the middle exchange rate, as listed, and charge less than 1% to do the transaction. There other companies that do the same thing, but I chose that company. They can transfer money from almost any country. They quote 2-4 days transfer time.
There is an extensive process, to prove who you are. Copies of ID's, Selfie with you holding your ID, etc.. They provide two or three ways for you to send them your U.S. Dollars. One way is a direct transfer from your account, another is a wire transfer from your account. I used the direct transfer, as my bank charges $15 for a wire transfer. I transferred $5,000 from my U.S. account and the total charges were $44.
I was very hesitant to use this method. But, the money, as they promised, did arrive in my Mexican account. Please, do your own research, but there are inexpensive ways to import money into Mexico. It could also be used to send money home, if you get ready to leave.