Inspired by Rob Cockerham's The Price of a Gallon.
Drink Size   Price Price/Gal. Brew-it-Yourself Starbuck's Coffee
Based on buying from amazon
and Rob's experiment 1 bag 16 oz. $9.50 $2.97
(brewed) Coffee Venti 20 oz. $1.70 $10.88 Grande 16 oz. $1.60 $12.80   Tall 12 oz. $1.40 $14.93 Caffe Mocha Venti 20 oz. $3.60 $23.04   Grande 16 oz. $3.35 $26.80   Tall 12 oz. $2.80 $29.87 White Chocolate Mocha Venti 20 oz. $4.30 $27.52   Grande 16 oz. $3.80 $30.40   Tall 12 oz. $3.25 $34.66 Espresso Doppio 2 oz. $1.75 $112.00   Solo 1 oz. $1.45 $185.60
I did the Grande Coffee one without a calculator.