With orders of $25 or more, Amazon offers Prime members the Kikkoman Soy Sauce 64-oz. Bottle for $4.99 with free shipping. That's tied with our mention from a month ago (although that didn't require a $25 purchase) and about the same price you'd pay for a 40-oz. bottle in locals stores. This sauce is certified kosher.
Note: This item is part of Amazon's "add-on" program and can only be purchased with orders of $25 or more.