I finally got myself a postal scale so I could start weighing my packages myself and printing out my shipping labels online. I am so glad I bought that scale, because it is so convenient! My business was just picking up to the point where it was getting annoying to go to the post office all the time and wait in line, then wait for the person behind the counter to get all the machines to work, only to have them scold me for my address label being too large or whatever. Now I just tape on my shipping label and drop it off at the PO. I also like the fact that there are little tracking links right in my paypal account activity, so I don't have to keep track of all those little delivery confirmation slips.
So, in conclusion.... best thing ever.