In the case of a letter, a universal rate is better and cheaper for everyone. Imagine the administrative costs of worrying about a one cent difference because you wanted to mail something to the wrong side of the street!
Of course, you mentioned parcels, so I plugged these numbers into the USPS web site:
10lb parcel with nothing special, from ZIP 48121 (Dearborn, MI) to ZIP 48089 (Warren, MI), regular service: $4.45.
Same package from ZIP 48121 (Dearborn) to ZIP 90501 (Torrence, CA): $9.43.
I think the best way for the government to finance government goods and services would be to invest in existing private companies. Buying shares of the 3000 largest publicly held US companies, or something like that, but not so many shares that it had a controlling interest in any single company.
That way dumb government management practices wouldn’t bankrupt the companies purchased by the government.
I liked this idea for quite a while. But I saw Greenspan in an interview where he was asked about the idea of government investing in private companies, and he had the viewpoint that most of the posters in this thread had: it is not desirable.
Now I’m thinking it’s a nice idea, but let’s face it… if the government accumulated wealth above and beyond what is needed in the next 1 year or so of operation, someone in congress would find some way to screw things up.