This web page is the perfect resource for calculating postage quickly.  This postage calculator factors in weight as well as shape based pricing.  This is an especially handy tool if you have a package that exceeds the weight capacity of your scale. 
>>CLICK HERE to visit USPS.gov and use the postage calculator.

If your like most people that deal with USPS on a daily basis, you’ve probably been acquainted with their many acronyms and abbreviations.  This is a great reference if you’re trying to figure out what some of these terms mean or just need a refresher.
>>CLICK HERE to visit USPS.gov and see thier glossary of mailing termonology.

Courtesy of the USPS, this handy list of topics gives you a great starting point into processes, rules, regulations, and even products for your mailing research.  These links are also in Adobe PDF, so you can save them to your computer or print them straight from your browser.
>>CLICK HERE to visit the United States Postal Service's official website, and take advantage of thier quick explanations of mailing regulations and processes.

This is a 28 page, full color catalogue designed by the USPS for helping beginners understand the intricacies of mailing.  I would highly recommend this document if you are new to shape based pricing and would like to know more about your mailing options.  It is also filled with tips from how to prepare mail all the way to how to save money. 
>>CLICK HERE to visit the United States Postal Service's website, and brief through this colorful starter guide.

If you’re looking to mail in larger quantities this page is a good starting point.  It contains a visual quick reference for shape based mail pieces.  Be sure to also explore the links on the left side for more thorough information on commercial mailing and standard/bulk mail. 
>>CLICK HERE to visit the United States Postal Service's official website, and read thier introduction guide about mailers for businesses.

If you’re mailing in volume, you can be eligible for special USPS discounts.  Before you can cash in on your bulk mailing discounts, you must first abide by the standard mail regulations.  This can includes special techniques when sorting and printing the mail. There are many configurations and factors that go into bulk mailing postage rates.  For more information on how you can use them to save you money contact one of our Commercial/bulk/standard, high Volume mailing specialists or call 1-800-243-9226.

>> CLICK HERE to visit the United States Postal Service's website to learn about bulk mailing.

This page gives you  the web version of the Domestic Mail Manual(DMM).  The DMM will give you everything you need to know about using the USPS to send mail inside of the United States.
>>Visit the official website of the United States Postal Service and read the definitive guide to the rules and regulations of mailing.

This page is a table of Contents for the web version of the International Mail Manual(IMM).  Here you will find out all of the specifics you will need to use the USPS to mail outside of the United States.   
>>CLICK HERE to visit the official website of the US Postal Service and discover the rules and regulations of international mail.