For the Hamilton Beach kettle, which is 1.7L and uses 3kW of power can cost on an average between 1.5p-7p per use dependant on electricity rates and how much water is being boiled at a time. Boiling one cup (~250ml) can take ~1 minute to boil and cost ~1.5p; whereas a full kettle (1.7L) can take ~4 minutes to boil and cost ~7p.

A good way to save money when using a Hamilton Beach kettle is to only boil as much as you need at one time or if you are boiling a full kettle's worth of water; use what you need and save the rest in a thermal flask for future use without needing to re-boil the kettle.