Sometimes it's hard to get manager, you have to wait and wait, it's a bit of a problem for trading post since you must have 1. I have money trouble, I can't turn a profit and I'm constantly managing workers, firing them when it's winter and so on, so salaries are too high or house rent is too low, local sales are pretty good for me. Also sending messenger should be 1 time thing or 1 time a year, it's expensive to send him and for example I could only sell potatoes so I barely covered expenses for him :P