We’ve just added a new feature to our WP e-Commerce Premium Shipping Plugin – “Shipping Overrides”.
Shipping overrides let you set special conditions on top of your Premium Shipping Rates, conditions such as Free Shipping, Minimum Charges, and Maximum Charges.
Each Override applies only to certain rates (For example so you could do Free Shipping for orders over $20 for local shipping, but make it only on orders over $100 for international shipping).
Some screenshots below – all feedback and improvement suggestions welcome!