It totally depends on your budget, your expertise in this (investment) area, your geographical location, etc.
Starting blank, without knowledge
The goal is to accumulate precious metals, for storing purchasing power. You are not going to get into collectables, investments or otherwise. Then you should aim for:
- - bars - general accepted bars (check the LBMA good list for the general accepted refiners, along with its trademarks stamped on the bars), so you can always exchange them anywhere in the world, under any condition, no questions asked. The bars have to be 99.5 at least, but most bars produced in the last decade are 99.99. Here a list of bars with their pictures.
- coins - Go for the most known coin in the world - the Krugerrand
The goal is to accumulate precious metals, for storing purchasing power. You may get into collectables, investments and otherwise, but the bedrock of your investments is bars and coins as listed above, and you should still refrain from going into any form of paper. Besides that, you may go for:
- - silver - Silver is just more volatile then gold, and you pay VAT on silver, making it less attractive compared to gold.
- coins - You may pick the locally known coins. E.g. if you are in France, you may go for the coins popular there. Remember the coins might not be recognized outside of France - so if you are forced to sell you may loose money due to that.
If you are up to it, you may consider going beyond "storing purchasing power". There are risks involved, so only "gamble" with money you can afford to loose. Any paper form is an IOU, with counter party risk associated with it, besides the normal risks like operational risk, (geo-)political risk, etc. The logical order of investments is to continue from risk-less to risk-full. Especially true for day-trading: Know that the vast majority of the participants will (statistically) loose money, as it is a zero-sum game, and the brokers are shaving off their part too.