Walmart offers the Stanley Adventure 16-oz. Stacking Vacuum Pint Glass in Green for $9.53. Opt for in-store pickup to dodge the $5.99 shipping charge. That's the lowest price we could find by $4, excluding the mention below. It features a stacking design for easy packing and keeps beverages cold for up to four hours.

A close price: Amazon charges $10.40 in Green.