Upvote:6
A quick search turned up the information below from Discover Baja
What am I allowed to take into Mexico?
When crossing by land, you are allowed to take your personal belongings and $75 worth of merchandise, duty free. People over the age of 18 may bring three liters of liquor or beer and up to six liters of wine. For more details, see our Mexican Customs section.
What am I allowed to bring back to the U.S. from Mexico?
Your personal belongings and $800 worth of purchased merchandise, duty free. If you are a California resident over the age of 21 crossing the border by car or foot, you may only bring back 1 liter of alcohol. Non-California residents over the age of 21 may bring back up to 60 liters of alcohol. California residents traveling via steamship, airplane or railroad may also bring back up to 60 liters. See our U.S. Customs Page for detailed information.
A search for beer prices in Mexico and California suggest that a beer in Mexico will cost you around US$0.50 (in local equivalent currency), while a similar beer in the US will cost between US$0.75 and US$1.00. (This wasn't a very thorough search, so I accept no responsibility for accuracy or otherwise)