My wife and I have spent a lot of time in Mexico. We lived in Mexico City for a year. Mexico City is huge. People are always worried it is dangerous, but that is like saying New York City or Chicago is 100% dangerous. In Mexico City you can stay in their really nice neighborhoods where movie actors and politicians live for $1500 a month. You can find nice safe neighborhoods for less. Mexico City has world class museums, theatre, restaurants, everything. A movie ticket cost like $2, the subway costs 15 cents and you can take a 30 minute taxi ride for $5. Even the he expensive restaurants cost a fraction of some overpriced American chain like Olive Garden! Lastly, if you need suits or other expensive clothing like that (I do, I am an attorney) you can buy them for way, way less in Mexico City. A nice, wool suit tailored to fit costs $100. I love Mexico City and have plans to return.
We also spend time in Zihuatanejo (Pacific Coast). This is a small town of approximately 50,000 people. It is touristy without being a resort. Lots of great, affordable restaurants. Fresh avocados, mango, blackberries, strawberries and other fruit from the market for super cheap. Fresh daily fish from the ocean. We take our entire family (Wife and three kids). A nanny for 8 hours a day costs 400 pesos (right now, that's like $25). We paid $150 pesos (approx $7.50) for hour long swim lessons for our three kids (all under five years old). We got a local photographer to take family pictures and give us all the digital prints for $1,000 pesos ($50). This was a really good photographer, btw.
I also recommend the colonial cities of Guanajuato and San Miguel de Allende. It will remind you that Mexico has a really cool mix of Indigenous, European and colonial history (which you see everywhere but especially in Mexico City and other major colonial towns).
Anyway, we are taking a 3 month sabbatical this year (our first taste of FIRE, we are about half way to our number). We will be using airline miles to get there and then slow traveling through Mexico. Our expenses will be lower in Mexico even with eating out and other splurges just do to the exchange rates and all that. Feel free to ask anything you need to know about Mexico.