This is my advice for people who want to prepare for realistic violence, financial upheaval, and various and sundry natural disasters. Consider it my response to having recently checked out some various Forums and Websites and seen the wallet draining bullshit that passes for "must have" knowledge to survive the in the 21st century.
1) Don’t do stupid things, hang out with stupid people, or go to stupid places.
2) Pay attention to what's going on around you, and learn to talk, walk, or run your way out of a bad situation before it escalates into a really bad situation.
3) Get some good OC spray and see how your particular unit works. Get a training unit at the same time and practice some drills with a friend or friends.
4) Get yourself to a practical self defense class and learn hand striking, kicking and even some standup and ground grappling. Lose weight, gain muscle, gain confidence, work some limited Force on Force drills on resistant opponents.
5) Get a 5 shot revolver, a used Makarov, a brand new Glock or whatever you can realistically afford. Practice with it semi regularly, carry it whenever possible. Get a pump shotgun for the house for heavy artillery. If you live in some rathole that doesn't allow this, then move as soon as you have accomplished Item 6 below.
6) Un-fuck your finances. Come up with do-able debt reduction and savings plans that you can manage to stick to.
7) Get 3-plus months worth of food, emergency cash and supplies stored up. The world might not come to an end, but your job sure might.
8) See your doctor and dentist regularly
9) Carry a flashlight and a knife or multitool. You'll be amazed at how you ever got along without them if you never did before.
10) Get your house/apartment as secure as is feasible. If there are blind spots, fix them, if the locks suck, replace them. As long as you’re not allergic to animal dander, a dog is one of the cheapest alarms you can install.
11) Take some Red Cross CPR and First Aid classes. Go for EMT if you have the time/money, or find a class teaching wound trauma management that covers tourniquets, occlusive wound bandaging, and wound packing. Carry a small, realistic first aid/trauma kit in your car or on you if you carry shoulder bag, backpack or attache case for work.
12) Take a defensive driving or accident avoidance course.
13) Learn something useful. Welding, computers, a new language, etc.
I'd rate all of those higher than running around with a $2,000 rifle, however much fun that can be. Also much more practical than taking a ‘Civilian Counter-Terrorist Course from your local self proclaimed “High Speed, Low Drag” instructor, and far better than worrying about zombie hordes. It will make you that much more of a self sufficient individual should such circumstances arise.