Interesting Expatiate Calculator
I found this calculator on Lifehacker.
According to it, its 20% cheaper to live in Bogota than Los Angeles. RT.com mentioned the median home price in Manhattan is $900K (apartment) no wonder HGTV is doing "Selling New York" show.
But these things are reflective of what the local currency can buy. Over on the Costa Rica Expat forums people complain about cellular handset prices, tanks of propane for BBQ's and other items that are easily found for less in America. I also find many expats receive "Care Packages" or make regular trips back to America because of this.
Its not surprising that housing is affordable in South America. But its also affordable in Berlin, Germany for example. It just depends on the local economic makeup.