What is the cheapest car to take when traveling across provinces?

Take the public welfare slow train.

This train has been running between the two places for more than 20 years and is still running. It is a public welfare slow train. The full fare of train 6026 is more than 15 yuan, but it only costs 1 yuan at one stop. The stop from Jiujiang to Xiaochikou, Hubei Province is already across the province. The 12-minute trip costs only 1 yuan. It is called "The cheapest train in history", you only need to spend 1 yuan to travel across provinces.