You can mail a letter or package under 16 oz. (unit of weight, 454g) in a mailbox, a blue box found on many street corners in U.S. cities and towns. Each mail box should have pick-up times clearly posted on top. !Packages over 16 oz. placed in a mailbox will not be sent. Bring the package to the post office or retail   mailing shop instead. The clerk will process if for you. The Post Office In the larger cities, when you go to the post office you must take a number and wait in line. Post offices tend to be extremely crowded around Christmas. Try to go as early in the morning as possible. Post office branches open at 9 a.m. and close at 5 p.m. while main branches close at 6 p.m. Buying Stamps ! The cost of a first-class postage stamp to mail a letter is currently 39 cents, although rates tend to change often. Stamps are sold individually or in booklets   of 10 (US$3.90) or 20(US$7.80) or in rolls of 100(US$9.00). You can buy stamps at the following locations: *online, if you have a computer. Link to the U.S. Postal Service website (http://www. usps.com) and click on "stamps online". *at your local post office *at some ATMs (automated teller machine) *at some supermarkets *by mail *retail mailing stores(you may have to pay extra for stamps and to mail packages through the U.S. Postal Service) Postal Rates and Fees The U.S. Postal Service's online postage calculator  tells you the cost to mail a letter or package anywhere in the world. But you should know the weight of the package and the post code of the package's origin and destination. If you don't know the weight of the letter or package to be mailed, you can go to your local post office and the postal clerk will weigh it for you. When do the post office main branches close?
At 9 p.m. At 6 p.m. At 5 p.m. At 5:30 p.m.