How much does it cost to run my oil filled radiator heater?

It is very difficult to accurately determine how much it costs to run a heater within your own environment. It depends largely on the type of house, size of room and quality of insulation.
However the maximum the heater will cost will per1 unit of electricity per hour, per kilowatt of heat. For example, if you have a1500 W heater the maximum it will use is 1.5 energy units per hour.
Oil filled radiators are more economical to run because they retain heat longer and power demand through the temperature control is called upon less frequently.
Electric heaters heat only the room you are in and not the entire house, providing extra heat only where required and helping to optimise energy consumption.
Electricity costs vary across suppliers. If you check your bill you will be able to find out how much you are paying per unit of electricity.