Gold ( including silver & platinum ) is a commodity, no different than coffee beans and is known as "high risk" in the investment world.
Only when you have a stable portfolio, ISAs and pension funds should you enter this market and if you do, try to keep you metals at no more than 20% of your other investments.
As a hobby, buy a few sovereigns or other gold coins when you have the spare cash.
When you get hold of your first sovereign for say £240, or tenth ounce Britannia for £100 and see how small the coin(s) is / are it you might start to wonder ....
You might prefer to start with silver - but know where to buy to avoid the 20% VAT so read the 100's of comments on this forum.
For the price of a full sovereign you can get hold of about 15 full ounce silver coins like Maples, Britannias, Eagles, Elephants etc.
You get a lot more weight and larger coins in silver and as silver appears artificially low in price right now there is more potential upside.
As a hobby, try both but ALWAYS do your homework before buying.