The US Post Office, which has lots of patrons grumbling about standing in line, does offer alternatives to the post office queue. Actually, a few of them.
The easiest way is flat-rate Priority Mail boxes. The postage is the same no matter how much it weighs. So as long as it fits, as the post office likes to say, it ships.
You can create a shipping label at usps.com, pay for postage online, and even schedule a free pickup the next business day using the Internet. Just leave the packages out by the mailbox for your carrier.
(READ the report at CS Monitor)