Very useful plugin and well worth it.
Some ideas to make it even better:
-Ability to preview the cost before ordering the label to verify that the correct label is being ordered. Maybe add a “Get Cost” button?
-Option to automatically mark orders “complete” when label printed.
-Option to mark shipments as “Product Sample” instead of “Sale of Goods” for those sending samples. Should also set product cost to $1 per item.
-Documentation of the plugin internals so snippets can be more easily made (to do all of the above ourselves).