Coin collecting is a hobby enjoyed all over the world. Coin collecting or numismatics is: "the systematic accumulation and study of coins, tokens, paper money, and objects of similar form and purpose. The collecting of coins is one of the oldest hobbies in the world" (https://www.britannica.com/topic/coin-collecting).
Numismatists (coin collectors) have collected coins for many reasons. Some study the coins for scientific purposes. Others enjoy finding rare or vintage coins. Others feel safer with gold coins, than with paper currency. Still others collect coins for long-term investment purposes.
Collecting coins for investment purposes is a lucrative way of utilizing a fun hobby. Numismatists purchase gold coins, silver coins, and investment coins, to sell later for a profit. Collecting coins on a short-term basis is not as profitable as collecting coins for a long-term investment.
For example, say a coin collector purchased nine silver quarters that were minted in 1965 for thirty dollars. If those coins were sold again in two months, they would still be worth thirty dollars. Now if those coins were kept in a collection, and sold ten or twenty years later, the value will be significantly higher, perhaps $100.00 or more.
(It must be mentioned that predicting the market value of a coin is not always certain. Although over the centuries silver and gold has increased in value, this is not always the case. Only invest what you can afford and spare.)
That being said: "Coin collecting is a $10 Billion dollar a year industry in the United States alone, and the world wide figure is somewhere around $100 Billion dollars a year. It is one of those hobbies that does not immediately pay dividends, but whose value is paid out fully in decades to come" (http://cointrackers.com/blog/3/coin-collecting-as-an-investment/).
Investment coins (coins purchased or found, and saved to sell later) can be gold, silver, bullion, or any other precious metal. If you are considering collecting, but do not have a large budget, one of the best way to start is to collect pennies. Wheat pennies (Minted from 1909-1959). In a penny box purchased from your local bank, for twenty-five dollars, 15-40 of those pennies are usually wheat pennies. Pennies minted before 1983 had a high copper content. These pennies are worth $.03 each. So, one hundred wheat pennies are worth thirty dollars, a five dollar profit, by only buying or finding pennies.
Many people do not use pennies. Often, they are just thrown on the ground. Finding a penny on the ground that was minted in 1910, is always exciting. These rare coins are worth more than three cents per penny. In the current market a penny minted in 1910 is worth forty-five cents to as much as thirty dollars. This amount varies due to the condition of the penny and location of the auction house. This is also the average price. There were four thousand Wheat Penny Proofs minted in 1910 which are worth $350.00. (http://cointrackers.com/coins/13498/1910-wheat-penny/)
Collecting quarters, nickels, and dimes are also a good investment. You can also purchase them from your bank, online, or at a coin shop. Going to a pawn shop can also be a great resource for coins, especially rare coins. Quarters, dimes, and nickels are made with silver. The higher the silver content, the more the coin is worth. A Walking Liberty Half-dollar is 90% silver and is worth six dollars and twenty-seven cents.
Gold coins are coins made entirely of gold. Historically coins were made of pure gold. A Gold Liberty Double Eagle minted in 1904, containing 90% gold, is worth $20.00. Gold rare coins are the most expensive coins to invest in, but have the largest dividends when sold later. One rare coin, a 1794 Flemming Hair Dollar, is worth $825,000.
Collecting coins is a fun hobby, but can also be a great investment. Coin collections can be sold in retirement or left to family in a will.