To determine which option is the best to buy, we need to calculate the unit price of Yogi's Yogurt for each option.
Option 1: Buying individually
Unit price = $1.09
Option 2: Buying a package of 6
Unit price = $6.39 ÷ 6 = $1.065
Option 3: Buying a package of 12
Unit price = $12.99 ÷ 12 = $1.0825
Based on the calculations above, we can see that buying a package of 6 is the best option as it has the lowest unit price of $1.065 per yogurt. Therefore, it is more economical to buy Yogi's Yogurt in packages of 6 rather than individually or in packages of 12.