Add a daily estimate. Move estimates to the right of the list item.

lib/models/expense.dart

@@ -12,6 +12,7 @@ class Expense {
       required this.frequency,
       required this.description});
 
+  @override
   String toString() {
     return "$name, $cost, ${frequency.title}, $description";
   }
@@ -19,4 +20,8 @@ class Expense {
   double calcComparableCost() {
     return cost * frequency.timesPerYear;
   }
+
+  double calcComparableCostDaily() {
+    return cost / frequency.numDays;
+  }
 }