I invested for a while with both bullion and coins. You can see if there is a bullion dealer in your area. If you have it stored with the dealer, it will cost you storage fees. One can also invest via commodities, but you should be fairly affluent in order to do that. You can lose everything in one day or less if you aren't careful. Commodity dealers will try to talk you into committing quickly for that reason, so unless you need a tax shelter, keep away from that.
If you choose to go with coins, it is usually rare coin dealers that you will buy the coins from and these coins are higher grade coins. Again, unless you know what you are doing, you could well overpay for these items.
Hope this helps!