It is possible to purchase labels with the exact amount in your One Balance account. However, this is only possible when purchasing from the BATCHES page.
This can be done on-demand or set up to automatically refill your balance:
If you prefer to complete the transaction on your BATCHES page, you can add postage to your account in the following ways:
On the BATCHING page:
If you return one or more shipments to the BATCHES page, you can work around this restriction. On the BATCHES page, select the Buy Label / Buy & Print Label option to allow the purchase.