It will depend on utility rates for each in your location, but in general gas rates are always lower than electric ones. Home cooking only consumes around 6% of the home's energy use, so either won't be a huge impact in your monthly outlay. HVAC, lighting, and appliances are the big hogs.

LWO - "in general" gas is cheaper, but I think this is only true in the Norhteast USA. Elsewhere electricity is much cheaper than gas per BTU of energy produced.

This does not take into account things like usability, equipment costs, of infrastructure one might need in their home for any given heating apparatus. There are wat too many variables with these to make a general statement with regard to cost.

The dual fuel range will be significantly more expensive to purchase than the same manufacturer's all gas range. Even if electricity is cheaper than gas in your area, it is unlikely you will make up the difference in the upfront cost. People are willing to pay more upfront because they really like an electric oven combined with the gas cooktop. I was not willing to pay more, and love my all gas range. I have never been convinced by the argument that electric ovens cooks certain foods better than gas ovens, unless maybe if you are a professional pastry chef. Just MHO.

Also, keep in mind the cost for the electrician to wire for the dual fuel range--that cost will vary widely depending upon your home's existing electrical wiring and location of the electric panel.

Gas is cheaper in my Texan neck of the woods.

Gas is also in general cheaper in the west.

Another possible factor is peak/ off peak electric rates.

Here is a link that might be useful: Gas vs Electric Appliances