Crossing a county line and watching the price change is a whole New York experience

I split my week between here and the city and I have started treating the drive as an accidental economics experiment. Same person, same week, same everything, and the number changes depending on which side of a line I happen to be standing on. Not by a little either. What gets me is that nobody involved seems to think this is strange. Ask about it and you get an explanation about costs and rent and taxes, and fine, but that does not really explain the size of the gap. Does anyone else deliberately time their errands around this? I am not proud of it but I absolutely do.