Living in Mexico is cheaper than living in US, but you still have to watch your budget or else you might spend more than you can afford. You will have to budget around $30/day, which should be enough if you are a backpacker and don't stay in hotels. Mexico has great food and drinks everywhere so you should definitely order a lot of these items to save money. If you are staying in hotels and doing touristy stuff, then your budget will be bigger.