In which city do you work? If you go to a big IT center in Brazil such as São Paulo or Campinas, $20k/year is just a little over the starting salary for a new grad from a top school. There's LOTS of worse positions, but this is not really that hard to find, considering that HN crowd is probably more qualified than the average developer...

That's true in Mexico too, if you work for small or local companies in a small/middle city, <$20,000 is almost the rule, but if you go to bigger cities, having enough English skills, with international companies, then salaries are incremented at least 100% (but still far from salaries in the US). That according to my experience, coming from an 800,000 citizens city to Guadalajara second biggest city in Mexico.

In the big cities the cost-to-live should be higher, maybe compensating the difference in salary. Is it?

The capital of El Salvador, it's the largest city of the country :|