Resistance heaters are typically cheaper than other technology, such as the electric radiator and convection heater. They are also more suitable for smaller spaces, such as a kitchen or bathroom.
The main factors that contribute to the cost of are the wattage of the device and how much electricity it will use per hour. Low wattages may use less electricity but be less effective at heating up a space. This is because they take longer to heat up your room's air when compared to higher wattages.