A bus signifies that part of our life journey that we are able to undertake in the company of others. More public than private, we perhaps have a common aim with the people with whom we travel.
Trouble with timetables, missing the bus, arriving too early, missing a connection all indicate we are not in control of our lives and perhaps should sit down and replan how we wish to continue. Dreaming of getting on the wrong bus, or it going the wrong way, shows that there are conflicting aims or desires that need to be considered and we should listen to our own intuition.
This is usually a warning of a wrong action, and we do not need to get carried away.
To dream of not being able to pay the fare signifies we do not have enough resources to set out on a particular course of action.
It may be that we have not paid enough attention to detail. You may also like to consult the individual entry for bus.