USPS First Class Package is a fast and affordable service to ship lightweight packages weighing up to 15.99 ounces to any U.S. destination. It offers nationwide delivery in three days or less, same as the USPS Priority Mail. The packages can be sent to any U.S. address, PO Box, and many APO/FPO/DPO destinations.
The pricing for the USPS First Class Package are based on the weight of the package and shipping distance. Extra charges such as fuel surcharges for residential or rural deliveries.
For lightweight packages weighing 15.99 ounces or less, USPS First Class Package is the most affordable and popular option with fast delivery within 3 days.
Use Postage Price Calculator – https://postcalc.usps.com/ to measure your postage cost.