are the flat rate boxes free

are the flat rate boxes free through USPS? Yes, USPS provides flat-rate boxes at no cost to customers. These boxes are available in various sizes, such as small, medium, and large, and can be used to ship items at a fixed rate, regardless of the weight (up to a certain limit). Flat-rate shipping is especially useful for heavier items that would otherwise incur high postage fees. Customers can order flat-rate boxes online or pick them up at their local post office.