Depends on the size of your house and what fuel you use to heat your home with.
Whether natural gas, electric heat, or fuel oil. Fuel oil is the most expensive and I've heard of some people paying $800.00 per month to heat their home with heating oil.
With electric some people pay around $500.00 per month and natural gas $300.00 per month.
When I was heating my home with electric my electric bill ran $175.00 per month but now I use a wood stove and I only pay $50.00 per month on electric.
I don't have natural gas heat either and only use wood heat for my sole heat source now so my cost to heat is almost zero per month, except the cost to haul the wood and cut it from my property the wood is free to me otherwise.
And sometimes I get free wood dropped off at my house or go and get the free wood that people no longer want that came from trees they cut down or storms took down.
My parents have natural gas forced air heat and they live in a mobile home. Their gas bill usually runs $150.00 per month.