I believe KoLMafia does not allow you to get the lowest price of an item so as to prevent mallbotting with scripts. However, it also provides several ways of utilizing the lowest price in the mall. The reprice/undercut CLI commands, as well as the "auto reprice" button in the Store Manager, will reprice max-priced items so that they are lower than the mall price (and a multiple of 100). You can also use the searchmall command to directly search for an item and its lower-end price distribution.
*Max-priced: 999,999,999,999 meat or whatever number KoL gives when you place an item in your store without specifying its price.