There is no metro in Thessaloniki. Buses are the most popular way of trasportation and are operated by the Organization of Urban Transportation of Thessaloniki (OASTH). Although the public transportation can be hectic, ticket prices are low. In conclusion, buses provide an easy way to get around.

You can find more info about the prices on the official website of OASTH: https://oasth.gr/en/fares/.