Amazon offers Prime members the Stila Smudge Pot 0.14-oz. Gel Eye Liner in Brown for $9.97 with free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping costs $5.48.) That's the lowest total price we could find by $6. It's waterproof and features an airtight lid.

Note that it's expected to ship in one to two months.