You can certainly use most barcodes in Designer without having to pay extra. All the barcodes are located in the Barcodes tab in the Library palette.
I believe the extra costs come into effect when you start using our Paper Forms Barcode technology which lets you encode field values into a 2D barcode on a form which will be filled-in electronically, then printed, signed (manually with a pen) and mailed/faxed back to your company. I believe you would then need our software to decrypt the encoded field values.
Other than that, you can put barcode objects on the form and set their properties using the Object palette. In particular, you can set their values at design-time (using the Object palette) as well as at runtime (using script) so if you know the value of the barcode that your form requires, it's simple.
Stefan
Adobe Systems