There may be anoyher reason other than what the other people have said.
You didn't say what type of gas you are using. If it is Natural gas you may have a minimum billing fee connected with it, which would add about $10 to your bill.
If your using Propane Gas have the tank checked for leaks around the Pressure Valve located ON the tank itself. than have them check the regulator and lines to your home. Propane is much more expensive than Natural gas.
I agree the a summer bill for gas stove and dryer should be between $20-$25/ month Maximim.
Something is definatel wrong to have a bill of $70-$80 per month.
I don't think yhe problem is in your stove unless your a professional baker. :)
