Is the Post Office a Business?

Sometimes, actually all the time, I wonder if the post office is an actually business.  They always keep raising postage stamps, they can't seem to ever keep all of their postal offices open (so many have been closed and maybe many of those shouldn't of even been open), and finally this one amazing me that they give all of their priority postal supplies out for free.  I guess they have calculated them in their costs of the shipping.  But mostly whenever I hear about the post office in the news I wonder if there is a businessman that is actually running it.  I mean do they really have any competition?  So honestly why do you need to raise prices all the time?  I mean really, is the United States Post Office a business?  (as a side note, I'm glad its not like many of the postal systems we hear about in south a