
You can buy stamps by the sheet and postage-paid Priority Mail envelopes. There’s an 8% discount on international Express shipping and a 5% discount for commercial Priority Mail.
The site also will send you — with no shipping charge — the boxes and envelopes you get for free at the post office. Once you have your stamped packages and envelopes, you can drop them off at a post office without waiting in line.
Through the post office’s Click-N-Ship service and third-party online vendors such as EBay.com, Stamps.com or Endicia.com, consumers can print out postage, at whatever rate their envelope weight and destination requires, on a laser jet printer at work or at home. If your mailing business checks, it will cost a little bit more.