Mexico is getting more expensive for the traveller all the time and now you’re really pushed to get by on $10 a day. It’s more likely that you’ll spend double that even if you stick to buying your own food from the market and hitchhiking around to avoid the cruelly expensive buses.
English teaching is definitely an option all over the country though you won’t get paid much more than $5 an hour in most schools. Papers aren’t a big deal and there’s plenty of demand with so many Mexicans dreaming of making money in the USA. Take a phone book and start hustling all the English schools you can find.
With so much tourism there’s also always work in the towns popular with travellers and holiday makers. You can take commission on bringing backpackers to hotels or getting them to sign up for boat tours and snorkelling on the beaches. It helps to have good Spanish for this kind of thing but your average tourist will trust a white face before a Mexican one. Sad but true.
There’s work to be found in hostels, too though it has to be under the table. You can make around $500 a month working 6 days a week but then life is more expensive in tourist towns and will eat up most of that.
If you’re into silver and stones then you can make a living here as an artisan, putting your own work together and selling it on the beaches. Even if you don’t know how to make stuff, you can go to the Mexican silver capital of Tasco and load up on silver rings and bracelets there. A few thousand dollars of silver fits into a small briefcase and you can either export or sell on the beaches if you’ve got the gift of the gab.
You can live cheaply by getting used to tortillas. They’re not the tasty, chemically-enhanced dough pancakes of Taco Bell, though but are rather thin and tasteless. Still, a kilo of them goes for less than a dollar and they keep most of Mexico from starving.