consider for example a little thing like a harmonica. i suppose that everyone has owned at least one, maybe it was a gift received during their childhood, or maybe it's something that you have had around in your house since forever, forgotten in a drawer. if so, there are good news. the harmonica you have owned since your childhood can become precious. i'm not suggesting the music section of ebay. what i'm saying is that if you become good enough at it you can go busking with a minimal equipment and earn some money, probably very little if you don't have the opportunity to play in front of big crowds but enough for a meal a day. you never know what it's going to happen in your life, so getting ready for anything (even for an economic collapse) is always a good move. probably you'll never need to go busking to pay your meals, but this is not an excuse for not getting prepared even for similar circumstances. a harmonica fits in your pocket, is cheap and relatively easy to play so it's a win-win situation. learning to play it is like having the cheapest life insurance you can imagine. surely you have to dedicate some time to learning how to play it properly, but it's like an investment, not in money but in time. and in these times of insecurity and global crisis the mere fact of knowing that you have a little ace in the hole to play in case you have to face severe economic difficulties can become precious. it will boost your self-confidence too.
obviously playing a harmonica (or any other acoustic instrument) is just an example, and music is just one of the many areas in which the same concept can be applied. the same goes for many other skills you can learn, just think of anything you can do to earn some money (or to obtain some other type of subsistence) without needing anything that you don't own already (possibly, even no electricity or fuel) or that you can easily obtain. consider something you're already familiar with at least partially, so you can start from a solid basis. spend some time refining your technique until you become very good, and the skills you learn will become part of your everyday survival equipment for the rest of your life.