A good one will have as few parts as possible, and be optimized for both portability and distances.

>Ferment your own alcohol from plants you grow yourself

I suppose I could just harvest gunpowder from the bullet trees that grow all over candy-land, too.

Or, I could just have an ultra-optimized trebuchet in my backpack for throwing things with very little effort besides the energy (me) required to reload it, wind it up, and let ‘er rip ..