well, we can see this case like this, say let's find out how much is it for just 1oz in each case.
[tex]\bf \begin{array}{ccll}
oz&\$\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
10.5&1.79\\
1&x
\end{array}\implies \cfrac{10.5}{1}=\cfrac{1.79}{x}\implies x=\cfrac{1\cdot 1.79}{10.5}\implies x\approx 0.17048
\\\\\\
\begin{array}{ccll}
oz&\$\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
16&2.19\\
1&y
\end{array}\implies \cfrac{16}{1}=\cfrac{2.19}{y}\implies y=\cfrac{1\cdot 2.19}{16}\implies \boxed{y = 0.136875}[/tex]
so, the one with less $/oz is the better deal, because is less bucks per ounce.
