To find out how much money the janitor will save by purchasing the used vacuum cleaner, we can subtract the price of the used vacuum cleaner from the regular price of a new one.
Regular price of the vacuum cleaner: $245
Price of the used vacuum cleaner: $113
Savings = Regular price - Used price
Savings = $245 - $113
Savings = $132
The janitor will save $132 if he buys the used vacuum cleaner.