I will show you how to build a Pocket Rocket Stove.
If you don't know what a rocket stove is, have a look at "rocketstoves.com" or search at Youtube where there are tons of very good videos to get inspiration from.
Step 1: Material List
1x oval bucket with lid
1x stove-pipe 120mm x 1 m
1x stove-pipe 130mm x 50 cm
10l hydro clay for hydroculture-plants
2,5 kg chamotte mortar
Everything costs about 35 EUR
bucket (for mixing the mortar)
bucket with the same shape as the bucket for the stove but slightly smaller