In addition to prepaid labels, we also have regular address labels, or unstamped labels. This shipping option is, as the name suggests, not stamped and therefore has no value. You will have to frank these labels yourself via a franking machine or with stamps. If you do not do this, you will receive a postage card from the carrier afterwards, on which they determine the costs for the shipment. It is also possible that some carriers unfortunately cannot send this shipment. PostNL is one of the carriers which always support this option.
If you want to test the Sendcloud shipping labels, this shipping option is the best option, as there are no costs for these labels if you do not send them.