Please note that you will not see the $13.98 price listed unless you select "subscribe and save" on the right hand side of your Amazon screen. Oh and did I mention there's FREE shipping?
Even though you need to subscribe to a monthly shipment to catch this deal, once your package(s) arrives you can choose to keep this scheduled shipment coming (but note the price is not guaranteed to stay the same) or you can cancel by going into your account on Amazon. You have no further obligations!
And FYI, don't panic when you get your payment conformation, it looks a little confusing because of all the deductions, but I promise it adds up... Here's my "bill" from ordering two 18 packs...
Item(s) Subtotal: $32.90
Shipping & Handling: $22.90
Shipping Discount: -$22.90
Promotion Applied: -$4.94
Total Before Tax: $27.96
Estimated Tax To Be Collected: $0.00
Grand Total: $27.96
And $27.96 divided by to is $13.98... So it worked out.