The USPS offers a variety of shipping options for small packages, including First-Class Mail.
First-Class Mail is the USPS's most popular shipping option for small packages. It has low rates for light packages, and it is suitable for sending items that weigh up to 13 ounces. Packages sent using First-Class Mail typically arrive within three days.
If you are sending a larger package, or one that needs to arrive more quickly, the USPS also offers Priority Mail and Express Mail shipping options. Priority Mail can be used for packages weighing up to 70 pounds, and Express Mail can be used for packages weighing up to 70 pounds. These services typically take two or three days for delivery, respectively.