Bulgaria is probably not a name that inspires tropical retirement dreams in the minds of most Americans. More likely, most Americans have no impression at all of the country, or if they do, the impressions were set when Bulgaria was a staunch ally of the former Soviet Union.
Times have changed. Bulgaria is transitioning to a free market economy, and in Europe, most notably the U.K., retirement in Bulgaria is a hot ticket. The nation which is a neighbor to Greece and Turkey boasts a real estate building explosion catering to foreign retirees, a low cost of living, and a coast on the Black Sea with beautiful white sand beaches.
In other words, Bulgaria is becoming to Europe what Mexico and Central America are to the US and Canada, an attractive warmer weather, value for money retirement destination with beaches.
Bulgaria will probably never be a popular choice among Americans, but it is interesting to see the same economic dynamic that is happening in America is also happening in Europe. We also include it as a case in point to Americans who are among the not-so-rich-and-famous set. Your peers in Europe are retiring to places like Bulgaria, not to high cost countries like France.
If you are curious enough to explore Bulgaria, there is a path to both buying Bulgarian real estate and also obtaining residency there. The businesses that specialize in helping expats are going to be more accustomed to dealing with people from the United Kingdom, but I don't see any reason why a determined American couldn't pull it off too.
This link suggests some of the requirements to get residency: