The factual information given about cost of living is based on a report of living conditions and salary adjustments published in the Economist. El Salvador is cheap compared to a world average of capital cities. It is behind a paywall so I cannot link it. You can access a pubic
domain source here.
which states:
Summary of cost of living in El Salvador
...
Cost of living in El Salvador is cheaper than in 65% of countries in the World (51 out of 79)
From your own link:
Cost of living in San Salvador is 34% more expensive than in Bogotá
Cost of living in San Salvador is 50% more expensive than in Buenos Aires
And that is the average, including the poor cities! If we go for the capital:
https://www.expatistan.com/cost-of-living/comparison/prague/san-salvadorCost of living in San Salvador (El Salvador) is about the same as in Warsaw (Poland)
Cost of living in San Salvador (El Salvador) is 6% cheaper than in Prague (Czech Republic)
Cost of living in San Salvador (El Salvador) is 5% more expensive than in Budapest (Hungary)
And are we really going to compare Prague to San Salvador?
This is exactly what Lucius was saying, compared to what, it is cheaper than New York or London or Tokyo but not so much cheaper than a lot of EU cities.
And there is no comparison in the quality of life between these!
As said, compared with the average. Furthermore, most expats are from rich countries hence saying cheap is correct in general sense. Anyway, data is there for whoever needs to figure out the cents.