Since USPS designates it for lightweight packages, it's the perfect service for sending out items like clothes, jewelry, and more. However, while you can get free packaging supplies for Priority Mail on the USPS website, USPS doesn't provide any boxes or envelopes for First Class Package Service.
Can you use flat rate boxes for first class mail?
Sorry! You can't use USPS flat rate boxes unless you pay for the specific flat rate service marked on the box. If you don't, USPS will charge you for the service marked on your box or envelope.
Can I ship first class in a priority box?
No, the USPS does not have boxes available for First Class Package Service. However, even with the cost of purchasing the box, you will still see immense savings using this option over USPS Priority Mail.
Can you ship first class in a flat rate box?
Sorry! You can't use USPS flat rate boxes unless you pay for the specific flat rate service marked on the box. If you don't, USPS will charge you for the service marked on your box or envelope.