Saving money as a South American

In most bus stations that I've used in South America, there has been a station tax that I've had to pay before I enter the departure area to get on my bus. Usually the fee has been around 50 cents.

Which is not a lot of money (you would think), but apparently makes a difference for a lot of poor people in these countries. It makes enough of a difference that almost every time I boarded a bus, the bus would pull out of the bus station as if to depart but then pick up people who are waiting outside to get on the bus.

These people already have tickets purchased and in hand, except they get on the bus outside the station so that they don't have to pay the tax. The bus ticket could be $20 but they won't go into the station to save less than 2.5% of the ticket price.

The whole routine is planned and understood by even the bus drivers. They know to pull outside the station and pick up a bunch of locals before they actually depart the city.