What is the difference between priority, express, and first class mail?

Question

I'm trying to send a package to la, but can't determine which one is the best option. So please help me.

Answer 1

Express Mail is the Post Office's guaranteed service.  When you mail it, the clerk will mark the guarantee information on the receipt and give you a copy.  If the piece doesn't arrive within the guaranteed time, you can get a refund (certain exceptions apply).  This is also the most expensive service.

Priority Mail is not guaranteed, but usually arrives in 2-3 days in most parts of the country.  Priority Mail is much cheaper than Express Mail.

Priority Mail is a subset of First-Class Mail.  If your package weighs less than 13 ounces, it is considered First-Class Mail.  If your package weighs more than 13 ounces, it is considered Priority Mail.  

However, you can pay the Priority Mail rate for a piece weighing less than 13 ounces, and it will be treated as Priority Mail in handling.