Unless you have very limited time in the country and need to rush from one attraction to the next, there is no need to pay for tourist transfers. Most of the iconic attractions in Bulgaria are accessible by public transportation, so just ask the staff at your hotel or hostel to help with the timetables. All the big cities are linked with buses or trains and sometimes both.
The national Bulgarian railway company offers discounts if you buy a return ticket, which is perfect for day trips. Most bus companies have special return fares, too. If you stay in Sofia and plan to use public transportation more than three times in a day, it is worth it to buy a daily pass (BGN 3/$ 1.5 USD) or a three-day pass (BGN 10/ $6 USD). These passes can be used for all public transportation (trams, buses, subway) and can be purchased at any ticket kiosk.
Uber doesn’t operate in Bulgaria, so cabs dominate. All the taxi companies within a city maintain more or less the same prices (though they vary in every city). The only way to save is to be careful not to hop in a fraud cab. Take a careful look at the fares that must be displayed on a sticker on the window of the car—if they aren’t there, move on.
Museums and attractions in Bulgaria will rarely cost you more than $3 USD, but if you plan to visit many of them, take a look at their websites for free days, which are usually once a month. All museums and galleries across the country are always free on European Museum Night, which takes place every year on the Saturday before or after May 18, the International Museum Day. There are many special events at this time, as well. Visiting churches is also free, unless it is a national monument. Same goes for the national parks.
Of course you’ll need to buy souvenirs to bring back home, but skip the tourist shops. Instead, head to the nearest supermarket, and stock up on lyutenitsa, a traditional Bulgarian spread made of tomatoes and peppers, and sharena sol, mixed Bulgarian herbs. Then, visit the beauty shop or pharmacy to buy cosmetics containing Bulgarian rose oil for a fraction of the price.
Take advantage of nearby fresh fruit and vegetable markets, and cook your own meals. Not only will it save you money, but you will also be happy to discover that unlike many countries where the fresh produce lasts longer but is somewhat bland, Bulgarian produce is rich in taste, though it rots quickly.
Many bars organize free live concerts with young bands. Ask at your hotel what’s on for the night. Many of the best Bulgarian festivals are free, too, and the parks, especially in Sofia, have many free events scheduled throughout the summer.