This chart provides information important to your decision making.  By referencing the second column, select the weight which most closely matches your dog's weight.  The adjacent columns will list how long the product will last, the amount to feed each day, and the cost per day. The 2 lb. Free & Easy comes with  handy 1 gram & 5 gram measuring spoons.  The chart for the 2 lb. Free & Easy is here.
 

Product Size Dog Weight (lbs) Product Duration (days) Amt. Per Day (grams) Cost Per Day
8 oz. 5 403 0.56 $0.09
8 oz. 10 202 1.11 $0.18
8 oz. 15 134 1.67 $0.27
8 oz. 20 101 2.22 $0.36
8 oz.. 25 81 2.78 $0.45
8 oz. 30 67 3.33 $0.53
8 oz. 35 58 3.89 $0.62
8 oz. 40 50 4.44 $0.71
8 oz. 45 45 5.00 $0.80
8 oz. 50 40 5.56 $0.89
8 oz. 55 37 6.11 $0.98
8 oz. 60 34 6.67 $1.07
8 oz. 65 31 7.22 $1.16
8 oz. 70 29 7.78 $1.25
8 oz. 75 27 8.33 $1.34
8 oz. 80 25 8.89 $1.43
8 oz. 85 24 9.44 $1.52
8 oz. 90 22 10.00 $1.60
8 oz. 95 21 10.56 $1.69
8 oz. 100 20 11.11 $1.78
8 oz. 110 18 12.22 $1.96
8 oz. 120 17 13.33 $2.14
8 oz. 130 16 14.44 $2.32
8 oz. 140 14 15.56 $2.50

8 oz.

150 13 16.67 $2.67
2 lb. 150 54 16.67 $1.60