How to buy barcode for amazon

If you upload your own cover and choose to provide your own barcode, it must meet these requirements:
Image quality:
Vector images* are preferred
Rasterized images** should be 300 PPI (pixels per inch)
100% black (not RGB/CMYK color or registration black)
Suggested size is 2" x 1.2" (50.8 x 30.5 mm)
Minimum size is 1.4" x .8" (35.56 x 20.3 mm)
Positioned at least .25” (6.3 mm) from the spine and trim of the cover
Solid white background
Right-side up and square to the cover
Image is not flattened into the main cover as a single image
* Vector images are comprised of "paths" that create the shape of an object with points, lines, and curves and which can be scaled up or down with no loss in quality. Objects like fonts are vector objects.
** Rasterized images are objects made up of numerous color-coded pixels which together make a single picture. Rasterized images cannot be scaled up or down without changing their resolution. Objects like .jpeg and .tif files are rasterized objects.
Note: Two-stage barcodes, typically used for Japanese books, aren't supported.