Taking Bus in US

I was out on holiday in the US. I am wondering why would I want to do that. Anyway, I think Mom was there as well. Seems we get around by bus from one shopping centre to the other. I was looking at the bus fare and try to figure out why the further destination is cheaper than the closer one. It is not much but a few $ is still a few $. So we decided to asked the driver, who was a wierd black guy. And he sort of telling us to punch in the code to find out about the fare. In the end, he sighed and punch the destination code, cause it took us a while to find it. And we finally hop on and get to the destination, still wondering why it is cheaper.