There's several free shelters that are planning to open in the event of a nuclear incident. I would cut out the middleman and build your own though.
There are plenty of places to get plans for such an endeavor.
I would highly reccomend lamp oil and sterno and such, along with propane and gasonline. Just store them appropriately.

Or you might not make it
to see the apocalypse.
Rope, clean water in opaque containers (50 gallon drums work well as long as they're suitable for potables.)
If you can afford it, buy two sets of heavy work overalls, one in the correct size, and one that's too big for you, but fits snugly over the other.
If you have to move around in a fallout zone, you want as much material between you and the dust as possible.
Candles and lots of of matches. An extra pair of heavy duty boots. Bandanas and scarves, for first aid and face protection. Everybody should own a
pair of welding or ski goggles. Consider style, you don't want to look like some prick from aspen when living mad max style.
Everybody should have a bangstick, scuba divers may know more about this, but an internet search should do it. And plenty of reloads.
A bow or crossbow is a good idea, because ammunition WILL be scarce. If the country does shut down and there's a run on the supermarkets, it might
be hard to find food. A sling or slingshot is a good idea as well, because unlike bows, they don't require speciailized ammunition. Practice!
A bicycle is a good bet, and extra tires.
Think about goods suitable for barter, and stock up on those especially. Things like batteries, powerbars, bottled water, clean hankerchiefs, MREs,
canteens, socks, and the list goes on.
There's several good lists available online.
One more thing everybody should have is a bug-out bag. Keep a backpack or satchel filled with a few days worth of essentials and local area maps
somewhere near the door. If you get word that you have to MOVE, it helps to be able to do so in a timely fashion. I for one would feel pretty silly
looking for clean socks with a nuke inbound.