You could opt for an expensive MRE, which uses water and a heating element to cook pre-packaged meals. Or, you could opt for a Baro Cooker, which uses the same technology to cook flamelessly.
Propane and Charcoal are out, of course, due to the carbon monoxide fumes both put off--don't use these indoors.
That leaves just to real choices for Apocalyptic cooking: Butane and Alcohol stoves.
Butane Cookers are used throughout Asia in many households. They utilize cans of pressurized Butane to produce extremely low amounts of carbon monoxide in the cooking process. They are however limited to how long they can be used at a time, and how big a cooking pot or pan can be put on them--heat radiated off the bottom of over-sized cookware can overheat the butane fuel canisters stored within the stoves, possibly leading to explosions.
Otherwise, these are fantastic for indoors use, provided you have a large area with some kind of ventilation--you wouldn't want to use one in a small area, enclosed area.
Butane stoves can be found in most stores with camping supplies, along with the cans of butane. They have variable flame adjustment, suitable for boiling water, or bringing something to a low simmer. Butane stoves like the one pictured below can typically be found for under $30.00
Alcohol cook stoves are considerably more compact than their Butane counterparts and burn even cleaner--depending on the fuel you choose. While not capable of outputting the heat of a Butane stove, and not having a way to adjust the flame, they take up far less space and are cheap enough to be purchased in sets of 2 or 3 for cooking multiple dishes at once. Alcohol stoves like the one below run between $9 and $20 each.
The greatest advantage the alcohol stove has though is its variable fuel sources. It can run on wood grain alcohol, denatured alcohol, rubbing alcohol, HEET fuel additive or just about any flammable liquid (note: not all fuels are suitable for indoor use). Using wood grain alcohol is considerably more expensive than rubbing alcohol, but produces a clean-burning flame. Denatured alcohol is the most cost-effective fuel, and can be easily obtained from your local hardware or home improvement store.