This is easier than it seems.
Many places sell gold. Usually in the form of gold coins or gold bars as well as jewelry. Gold coins are bars generally make the best buy. Jewelry is virtually never pure gold (except for some Asian manufactured jewelry such as rings) and has a high retail premium or mark up.
Some of the best places to buy gold are, dealers, mints auction sites, coin collecting and numismatics clubs. These places will usually offer the best deals and with a little browsing and some due diligence, some great bargains in gold can be had.
What sort of gold you buy will depend also on what sort of gold you would like to have. Some people specialize in collecting certain gold coins, such as Krugerrands, Gold Eagles, or Maple Leafs and Sovereigns.. Some specialize even more and collect particular types of one of those coins. Other like to collect gold bars. Some collect gold through exchange traded funds or a gold provider such as GoldMoney.com. Others just collect whatever gold they can lay their hands on and are not fussed about the type.
The important thing is to have some knowledge about gold, and how it is fabricated and presented, how much it is going to cost to acquire and how much you can afford to spend on a regular basis.
There is a wealth of information on this site specifically aimed at helping you to find out what the best buys are when it comes to gold and what to look for. How to ensure you are getting the real McCoy and how to ensure you do not pay more than you should.
If you have more money than you can throw a stick at, then acquiring gold is not a problem. You simply buy gold in large bars and have them stored for you by a bank. This would be done, of course, in conjunction with advice from your financial planners. The small buyer of gold can simply buy a few well chosen coins or small bars from a dealer or mint or scour the auction sites for a good deal.
Best of all, finding gold can be a fun experience and there is a great deal of satisfaction and pleasure to be had when you buy gold, and it is delivered into your hot little hands!