How to Offer Free Shipping
You may want to provide Free Shipping once a customer's order value is greater than a certain amount. Let's say that if a customer spends more than $100, you would like to offer Free Standard Delivery. To do this, simply create a Postage Rule called something along the lines of "Free Standard Delivery on Orders over $100" with a Minimum of $100.01 and a Maximum of any greater value (the system automatically sets the final band in a Postage Rule to "unlimited", so any order over $100 would still be covered by this Postage Rule, even if the Maximum was set to $100.02).
However, please note that you may still need to create additional Postage Rules for this price band to ensure that your customers are offered the correctly priced options for any alternative shipping methods you have, such as Next Day Delivery or International Shipping. Alternatively, you could add Free Shipping as the final band of any existing Rule.