Convert pounds to ounces:

$\displaystyle\text{6 pounds}\cdot\frac{\text{16 ounces}}{\text{1 pound}}=\text{96 ounces}\usepackage{cmbright}\Huge\$

Calculate the cost:

$\displaystyle\text{\$0.44 + \$0.20(95) = \$19.44}\usepackage{cmbright}\Huge\$