Never been to bansko, but been borovets. I sure there all similar in this respect. A hot wax is usally about 5 lev, edges about 15 lev.
Should be loads of places to do it, its a ski resort! But certainly, some ski techs are better than others. Others here should know wheres good. Getting the edges done here in Uk is only about £10, its an option!
Learn to do it yourself. Not vey difficult and cheaper. Also you know your using quality wax and its done well. Won't be taken for a mug either.
Take some zardoz notwax with ya too.