I recently planned to fly to Greece via Sofia but their price was ridiculous at something over £200. Like Tirana in Albania, the bill included stuff like runway lighting.
There seems to be a shortage of airports which have both customs and avgas. I hope they improve things; they can because they are starting with a post-communist clean sheet. So long as they don't employ some UK empire building airport manager who promises them a 737 a day and then kicks out GA
Croatia did it right, which shows it is possible.