for a Federally regulated entity, USPS is super fickle. I have shipped packages first class through usps.com before and have had no problems. When I was in line at the post office the other day, I saw a guy shipping a bunch of flat envelopes with DCN's and I couldn't help but wonder WHY there are all these 'rules' if no two post offices ever do things the same.
Anyway. I got a postal scale for $2 at an estate sale of a dead doctor. I also got a bunch of sweet glass jars and vintage medical instruments
It was a great investment and I'd say it's definitely worth the $30 or so that most stores sell them for!
oh, and I am about 1 hour away from being finishing up all my soaps...finally!