It is an actual question: how much electricity do slow cookers use? First of all we need to determine: electricity consumption of a slow cooker is 500 W/hour (average value). There are models with different consumption (+- 100 W), but the average value is 500 W/hour.
It is not much, but it is necessary to take into account that slow cooker need a lot of time to cook food. Some models can cook for 3-4 hours, and some dishes require altogether 12 hours (maximum). So despite the power usage of the device is small, it may use much electricity due to a large cooking time.
How much does it cost to use a slow cooker?
The average price per kilowatt is 15 cents. We will use this value. If the power is 500 W per hour, it means that during 1 hour the device will consume approximately 350-400 watts (due to work mode: slow cooker turns-on and off during cooking). So one hour of slow cooker work costs about 6 cents. The cooking needs 3-4 hours in average. So user will spend about 18-24 cents.
Now look at electric oven. Energy power of this device is 2-3 kW/hour (average), but there are also ovens with a great power usage (about 4 kW). We use an average value 2.5 kW/hour. In one hour device will consume 2 kW that will cost about 30 cents. If the power usage of oven is 2 kW/hour so 1 work hour costs about 23-26 cents. One hour is enough to cook food due to a large temperature inside. But it depends on the dish.
So we see that slow cookers don’t use much electricity and they are more economical. But all values are the average and this calculation is approximate.