How much a difference would a price decrease or increase make in your monthly electric bill?

The U.S. Department of Energy is part of the federal government, of course.  One of the programs the Department of Energy operates is The National Renewable Energy Laboratory, which does energy efficiency research.

NREL operates a website which gives people information about electricity rates charged by utilities across the country.  Information about electricity rates in Decorah is at: https://www.electricitylocal.com/states/iowa/decorah/
This allows you to see the rates charged by Alliant Energy in Decorah.  It shows the average commercial customer is charged $0.0901 per kilowatt hour; the average residential customer is charged $0.1299 per kilowatt hour and the average industrial customer is charged $0.0578 cents per kilowatt hour.

(Alliant Energy spokesperson Mike Wagner wants to refute the rumor that rates charged in Decorah are any different than rates charged in the rest of Alliant's service area.  He says, "I keep seeing that people think that Decorah customers for Alliant pay more than Alliant customers in the rest of our service area. And it simply is not true. All of our residential customers are charged the same rate.")

So let's say you're a residential customer using 500 kilowatt hours a month of electricity (higher in the heating and cooling seasons, lower in spring and fall, but averaging 500 kilowatt hours).  You're paying around $65 a month to buy electricity (there are other charges which make your bill higher).  If that price goes up or down by one cent per kilowatt hour, you're saving or spending another 65 cents.  You can find your own latest electricity bill and do your own calculation, looking at the total kilowatt hours you used in the last month and multiplying that figure by 0.01 to see how much a one cent change in price would affect your bill.

Of course, commercial or industrial customers use a LOT more electricity, which is why they get the "volume discount," so a one cent per kilowatt hour change would affect them much more.