Taxis in Bulgaria are all painted bright yellow ( or gold) and are usually branded to a particular company. They charge by the kilometre, with an initial fee of anywhere up to 1 lev. A cap on the price per kilometre has recently been imposed and will be around 60-80 stotinki daytime and slightly higher at night.
Once the biggest rip-off merchants, many still cannot resist the temptation to take advantage of a disorientated tourist. Do make sure you have seen the price per kilometre and keep your eye on how the price is going up as you are travelling. Your taxi driver is obliged to display his photo and I.D. on the dashboard as well as a number for you to call with any complaints.