Raise your own Tilapia. The species is well-suited to container farming. Tilapia are not only easy to breed, they are also very efficient at converting food and they grow quickly. Lots of tips in this interesting article.
When they ban guns in the US...a South American homemade "one-shot" shotgun (a.k.a. Hechiza), frequently used by the Mapuches (indigenous inhabitants) in the south of Chile in their recent battles against the government. The ammo is allocated in the smaller front tube, and is then pushed inside the rear bigger tube, where at the end is velded a nail, so as the ammo hits the nail it ignites the primer. Total cost for this weapon: five dollars.