Example:
use Barcode::Code128 'FNC1';
$code = new Barcode::Code128;
$code->text(FNC1.'00000123455555555558');
This is CODE128 which may not be what you want if you are trying to print barcodes for retail purposes. In the US you would want to use UPC-E (for those reading from Europe, this is similar to EAN there). Different barcode scanners encode information differently so using the wrong type will result in problems.
Also note: Most barcode decoders (on-scanner or otherwise) have to be programmed to know what sort of barcode they are expecting so you don't want to mix these in an environment.
