It depends on a lot of variables, like what exactly you're shipping. USPS.com offers some basic guidelines for their shipping times on various different packages and sizes.
Sent a USPS package CW186232608US to a business in the Domincan Republic. They report not receiving it. Package sent April 28 2012 it is now May 24. Who do I contact to track the package?
If you get that kind of postage. They will normally use the ground ship
1 to 14 days or more
It should arrive in about 4 days. However, there can be conditions which result in delays, such as weather. Your best bet is to call the post office and ask.
USPS can be 3 to 5 days. No mail on Sunday.
about 4-7 days
If you had a package delivered by the USPS and it isn't at your home, you need to contact them and ask where they left the package.
If the United States Postal Service (USPS) loses your package, they are responsible for it.
from my experience, it took 3 days not counting the actual shipping date.
The abbreviation for Missouri is MO.
USPS flat rate boxes are shipped priority mail. Your package will arrive in 2-3 days.
You can use USPS, UPS, or Fed Ex. Or you can use third party website such as Shipinar.com that resells these shipping labels.