I am returning to selling on Amazon after a long time and I am astounded at the difference between how much shipping is supposed to cost (according to Amazon) and how much it actually does cost when I go to the post office. The solution seems to be "buy shipping," but there's something missing from all the articles and videos on this topic ... what do I do with the package once it's all labeled and ready to go? Am I still just taking it to the post office or using a UPS drop box on the corner (those have always seemed sketchy to me). The videos seemed to imply that there was a better option ...