Outside of graphic art and music (and beer/alcohol making) - some of the crafty things I try/do are simple or relatively simple projects to help save money.
One more recent example was around a year or so I saw a few youtube videos on people using "candle heaters", and decided to give it a go. The first experiment was just with 3 terracotta pots of increasing size inside each other, heated by a candle. Really not much heat - and not nearly enough to heat a room. So I improved it and cut a length of steel (threaded) rod - and added some washers and bolts - and stuck it through the top hole, and sealed off the top. Better - more heat, but still not enough. Replaced candle with a thick glass container filled with pure alcohol, that burns through a wick that comes through a hole I cut in the top cap. Better still - more heat - but not enough.
Because the heat hasn't been enough - I've still been using my oil heater - which costs a fair amount of money to run (electricity is not cheap in Aus). So this last week I bought an even larger terracotta pot to put over the original design, laid out on bricks, and minimizing to a degree the inlet air. This version is more successful, and it's heating my study right now. I still feel it can be improved though, and will probably try this next year: