Maximize Cost

An online wholesale shop of metal rods follows a sale strategy such that the cost of a rod is inversely proportional to its length. That is, larger the rod length lesser the cost. The shop receives a rod of a certain length each day along with the cost of that length on that specific day, i.e. $Day$ $1:$ Length $L_1$ and cost of length $L_1$ is $C_1$, $Day$ $2:$ Length $L_2$ and cost of length $L_