Outside Sofia salaries are much lower but depends on the city, the smaller it is the lower the standard.
Look again http://www.investbulgaria.com/CostOfLaborInBulgaria.php as you see it shows salaries for Plovdid also and they are very close to those in Sofia, but again depends on the city. And it says "salaries in BG have been on the rise in RECENT YEAR' . things are evolving...if you lived in BG 2 years ago you might have a different impression.
Regarding the rip off it happens to locals too, not only foreigners but as you say it doesnt take long to learn things.
Look again http://www.investbulgaria.com/CostOfLaborInBulgaria.php as you see it shows salaries for Plovdid also and they are very close to those in Sofia, but again depends on the city. And it says "salaries in BG have been on the rise in RECENT YEAR' . things are evolving...if you lived in BG 2 years ago you might have a different impression.
Regarding the rip off it happens to locals too, not only foreigners but as you say it doesnt take long to learn things.