Create a non stock item (service) for each type of postage, assuming that you have a default price for each.

  1. To create a non stock item (service), go to Inventory > Parts.
  2. In the top right corner, click the drop down arrow and select New Service. Enter the relevant information as if it was a stockable product. Click Save when you've finished.
  3. If you want to create this within any document (SO, PO etc) use the drop down arrow near Create Part and select Create Service.
  4. When you add a service item to a SO, it will not show on the packing stage, nor will it show on a receiving stage from a PO