The price recommendation calculation will be very simple: given an item title and city, return the most frequently occurring list price value (the list price mode: https://en.wikipedia.org/wiki/Mode_(statistics)) for that item set along with the total count of the returned item set (i.e. how many shoes are listed in Miami). If there is a tie (i.e. multiple list prices have the same number of occurrences) return the highest list price value.