\(\begin{array}{c|c}
\text{Opening stock} & 1800 \\
\hline
\text{Purchases} & 2800 \\
\hline
\text{Sales} & 800 \\
\hline
\text{Closing stock} & 800 \\
\hline
\text{Carriage on sale} & 500 \\
\end{array}\)

Calculate the value of the unused stock