With orders of $25 or more, Amazon offers Prime members the CorningWare 20-oz. Mug
in French White for $4.97
with free shipping
. (Non-members can qualify for free shipping with orders of $35 or more.) That's the lowest total price we could find by $2. It includes a lid and is oven-, microwave-, refrigerator-, and freezer-safe.
Note that this item is part of Amazon's add-on program and can only be purchased with an order of $25 or more.