Display cost per unit

templates/main.html

@@ -32,7 +32,7 @@
         <div class="smart_meter">
             <div class="smart_meter_info">
 {#            Implement some way to display "No devices" message if none are in use#}
-                <p> Cosr per kWh: {{ cost_per_kWh }}</p>
+                <p> Cosr per kWh: £{{ cost_per_kWh }}</p>
                 <p> Total energy used today: {{ daily_total }} kWh.</p>
                 <p> Total cost of today's energy usage: £{{ todays_cost }}</p>