Does USPS charge for a box?

Hello there, I'm curious about something regarding the United States Postal Service (USPS). Could you please clarify for me if there's a fee associated with acquiring a box from them? I've heard mixed information and would appreciate a definitive answer. Is it a standard charge across all services, or does it vary based on factors like size, type, or the specific mailing service I'm using? Thanks in advance for shedding some light on this matter.