If you have users that are local to your shop, or perhaps are visiting from another part of the state, Loupe allows you to flag those users as "Local Pickup" buyers. This will remove the customer-paid shipping costs for all purchases until you remove the flag. The customer's state in Loupe must match the state from which the shop is based.
To enable this, simply click "Users" and search for the associated buyer's name. Select their name on the list, and then ensure they are listed as Local Pickup enabled.