Hoard things of intrinsic value. Precious metals, gasoline, jewels, canned goods, ordnance, guns, high-end knives and swords (such as Gurkha blades, samurai swords, Ginsu steak knives, Cutco, blades with surgical edges), compound bows, land, livestock, auto parts, tools, and then currency becomes marginalized-but-still-there in a low-tech sub-economy that exists off the radar.
Learn how to make EMPs.
Learn to upload malicious code.
Get in excellent shape.
Advice for a character in a dystopian SciFi flick…
That's good advice.. I bought a small tractor, loader, backhoe and tiller.. In hard times maybe folks will need a garden tilled.. That's where I come in.. :)