Comparing energy plans is usually free when you use an independent government service such as Energy Made Easy, although some commercial comparison sites may receive commissions from retailers. The potential savings depend on your location, energy use, tariff, discounts, supply charges and the rates available when you compare. Use a recent bill to enter your actual usage and check the estimated annual cost, contract terms and exit fees rather than relying only on headline discounts. Before switching, confirm the offer and any applicable fees directly with the retailer.