The thing to buy is junk metal. That is quarters and dimes dated 1964 and earlier. These are 90% silver and are real currency. A dime is 1/10th of an ounce. A quarter is 1/4 of an ounce. There are also half dollars and other amounts such as small bricks or bullion.
To check value go to internet and type in spot price silver or spot price gold. You will get the price for one ounce at that exact time and it is listed internationally. The dealers usually charge 2% over spot. Don’t know what will happen when SHTF and how things will change. This is how it is right now.
Do NOT buy through the Internet! The prices are much higher and there is a paper trail… Buy cash from a local, reputable dealer. You keep them reputable by knowing the spot price and asking how much over spot do you charge?
For gold there are 1/10th coins that can be purchased. They are the size of a dime.
We chose silver because it is used in many industries and many say it will go very high in price. There is more demand for gold but it is usually out of the normal persons price range. Gold is not used as much industrially.
Never buy coins for historical or numismatic value (collector value) that is all trash now. You are paying for the purity and weight. It should be stamped with purity and weight right on the coin or bullion. You can read articles on the net.
Stock up on items that one can barter with such as soap, candy, coffee, tea, beans, sugar, detergent, etc. This is a good article to read about The Russian financial crisis in 1998 http://en.wikipedia.org/wiki/1998_Russian_financial_crisis
One item that is always in demand especially during rough times is alcohol (the kind you drink) of any kind. In depressionary times alcohol consumption goes out the roof!