Metro Bus

The Metro Bus system is a common mode of transportation for many Panamanians. The company promises service, comfort and efficiency at a low price. The cost to ride the bus is a low 25 cents.  However, most of the time these buses are packed as tight as a sardine can, with the majority of the passengers hanging precariously from the overhead supports.  It will get you where you need to go but don’t count on a comfortable ride, especially during peak traffic hours. 

http://ptylife.com/metrobus-panama/