A small space heater which uses gas and has an open flame. This was the type of space heater we used for well over a decade. It was great for heating a space rapidly, but a little dangerous. The cost is $194 U.S.
I know that foreign folks are renowned for whining about the lack of central air conditioning and heating in many parts of Japan. People who criticize these complaints think that the Japanese are saving energy by not heating up their entire homes, but that only works if they aren't heating their homes using other methods and if inefficient space heating methods aren't being employed. Given the lack of insulation, and the inefficient energy consumption of space heaters, kotatsu, and heated carpets, I'm not sure that not employing central heating is really doing the planet any favors. Well-implemented central air and heating and good insulation would almost certainly be less wasteful energy-wise than current space-heating methods in Japan.
I won't miss seeing my breath in the kitchen in winter and sweating myself stupid in summer because only one room in my apartment has heating and air conditioning.