Lonely Planet recommends using the public transport system of Budapest, Hungary, as your own personal sightseeing tour, especially since many of the bus and tram routes pass Budapest's most famous views and monuments. Plus, as of 2022, a single bus ticket only costs 350 Hungarian forints, which is about $1.

Budapest, Hungary

Known for its museums, historical attractions, and stunning hikes around Mount Vitosha, Sofia, Bulgaria, is filled with secrets and pleasant surprises, with far more to offer than what you'll see at first glance. Dining and accommodations are well-priced, museums are about $3, and a day ticket for transportation is only $2.

Sofia, Bulgaria

With fairy-tale spires and charm, Tallinn, Estonia, has free museums, and many of the city's most interesting sights can be seen from the street, like the Danish King's Garden or the Cat's Well — once a place of sacrifice to keep a local water spirit happy. Great views of the whole city are free to visit on Toompea Hill.

Tallinn, Estonia

Known for its gardens, museums, and impressive main square, Kraków, Poland, has accommodation between $56 and $86 a night, street food like zapiekanka for loose change, and bar drinks for about $1. Notable historical sights include the jaw-dropping Wieliczka salt mines and the Auschwitz-Birkenau Memorial and Museum.

Kraków, Poland

There's plenty to do in Porto, Portugal's second-largest city, including visiting the nearby beaches and hilltop views for free, and a one-way trip on public transport costs just over $1. There are plenty of comfortable budget hotels for much less than $100 per night, and the city's tabernas offer classic Portuguese food and wine at great prices year-round.

Porto, Portugal