By taxi
Many taxi drivers know only limited English so it is useful to write out your destination or carry a map. In winter 2008, a few of the newer taxis in Sofia have GPS units on the dashboard. Taxi tariffs in Bulgaria are standardized in the major cities. One should be extremely careful about using a taxi in Bulgaria. Especially since you are a foreigner, you can definitely become a target of unscrupulous taxi drivers. When in need, get familiar with the most well known taxi operators in your area, your route and expected bill. Generally the safest way of using a taxi is by ordering a taxi by phone. Some fraudalent taxis even mimic others' logos and labels on their cars. Definitely avoid using taxis waiting at airports and railway stations! An exception represent the Sofia and Varna airports as recently both airports contracted with licensed taxi companies. Currently only these companies can enter the airport area and pickup passengers - prices are standard.
By train
Travelling by train is inexpensive, but also slower than by bus. Trains are most useful when travelling along the two major train routes: Sofia - Varna and Sofia - Bourgas. You can travel both routes overnight, but you should make your reservations early because these night trains are often fully booked.
The official website of the Bulgarian State Railways (http://www.bdz.bg/) is user-friendly and offers an easy-to-use online timetable (http://razpisanie.bdz.bg/...). Another train planner is available on www.bgrazpisanie.com (http://bgrazpisanie.com).
Recently, new equipment has appeared on some the trains on routes between main destinations. New rail lines are also under construction but will not operational until 2011.
There is discount for travelling in group.
By plane
Air travel is still not very common in Bulgaria as distances are relatively short.
Bulgaria Air, the national carrier travels everyday from Sofia to Varna and Burgas. Off peak deals can be found for 25eu r/t after taxes
WizzAir travels four times a week between Sofia and Varna. Off peak travel can be as cheap as 20eu r/t after taxes
Their timetables can be found on their official websites or altogether on BGrazpisanie.com (http://bgrazpisanie.com)
By bus
Certainly the fastest way to travel around the country is by bus. Buses go from and to every bigger city you might have to ask or be driven by taxi to the bus station quite frequently exact timetables information in English can be found at avtogari.info (http://avtogari.info/index_en.php or BGrazpisanie.com (http://bgrazpisanie.com)); however, most bus station agents except at the Black Sea and in Sofia as well as the drivers will not speak or understand any languages except Bulgarian and, if you are lucky, Russian and the destinations will be written exclusively in Cyrillic. You can look up bus schedules for the Sofia New Central at the bus station (http://tis.centralnaavtog...).
Travelling from Sofia to major cities in Bulgaria by bus is a good value. A one way ticket to the Black Sea from Sofia is around EUR 12-15. Several companies operate regular routes serviced by new and modern buses. Timetables and prices in English for couple of the major companies can be found at GRUP Plus (http://etapgroup.com/grup/en/) and Biomet (http://www.biomet-bg.com/...).
There are other bus stations in Sofia and also some private buses depart from their own personal station, but for travellers just looking to get out of town with the least amount of confusion - using the New Central Bus Station may be easiest.
Buses and Minibuses go from Varna and Bourgas along the coastline, passing or going to all Bulgarian Black Sea tourist resorts.