Depending on what printer you have, you can generate all your label files on a 4”x6” page (choose this for label printers) or A4 page (choose this for home laser printers).
You can find this setting above the Confirm and pay button so you can update this setting before you are about to purchase a label. It should display the setting you have now (4”x6” or A4). Click on Change to update it.
In the Bulk Shipping tool, setting this to A4 will generate your labels with up to 4 labels fitted on one A4 page. This will save you paper!