I had little coke can penny stove I made for my kit together with an old nasal spray bottle with one charge of meths in it for fuel.
Mine burnt for 10 minutes which is enough time to boil a liter of water (just).
I tried lots of different designs from Wiki and
http://www.zenstoves.net before I got it right though. One experiment went "pop" dramatically and sprayed me with burning meths so be careful whoever wants to experiment.
I've also got a simple Altoids tin stove.
Basically fill a tin with fiberglass insulation and cover it with cut up metal mesh (mine from an old kitchen flour sifter). Add 30 mils of anything. Petrol, meths, deisel works (but gets a bit smoky), and I've even used rubbing alcohol. 4 x 6" nails makes a pot stand. Boils a liter of water in 8-10 mins.
The beauty of the altoids tin is in the lid. Blow it out, tip out any liquid, close the lid, and you don't have to worry about a smelly stove in your kit.