Dan had $ 3 left with him after he bought a candy bar. If he had $ 4 at the start how much did the candy bar cost?
$$
\begin{array}{l|l|l}
\text{Step} & \text{Condition} & \text{Calculation} \\
\hline
1 & \text{ } & \text{ } \\
2 & \text{ } & \text{ } \\
3 & \text{ } & \text{ } \\
4 & \text{ } & \text{ } \\
5 & \text{ } & \text{ } \\
\end{array}
$$

A: The candy bar cost $1$.