Believe it or not, coin collecting is actually becoming a very popular hobby. It's definitely not as popular as sports like basketball and football, but coin collecting has actually managed to create a subculture of sorts among the American population and around the world. In fact, collectors prefer some coins to others, sometimes because of price, sometimes because of ease. The most popular US coins to collect tend to be the ones we see most often and last the longest.
By far, US dollars are the most popular among collectors. The rarest US dollars also double as the world's most valuable coins. Morgan dollars, dated 1878 to 1921, are some of the most sought after coins that are still at a reasonable price range. The oldest US dollars collectors look for are called Early Dollars, and they are dated 1794 to 1804. Needless to say, these coins are some of the most expensive. They can cost over $100 without any problem. Some reach around $1000 with competition in the bidding process, and a select few rise up to over $50000. The most common US dollars we will see are Sacagawea dollars, which were first issued starting at the turn of the 21st century.
US quarters happen to be a popular place to start among the younger coin collectors. It's easy to collect these quarters, because these collections start with the 50 states and then move into other quarters. US quarter collections also have a considerable amount of depth because they don't stop at just the 50 states. They can then move into categorizing by year and then by different errors and marks like regular coins. The US Mint released commemorative quarters for five states every year from 1999 to 2008. US territories received commemorative quarters in 2009.
Surprisingly, nickels are also quite popular. Jefferson nickels, which were issued by the US Mint starting in 1938, are the most popular nickels to collect. Jefferson nickels last a very long time, unlike other coins, so they are also great ways to start for younger coin collectors. Currently, every single year's Jefferson nickel from 1938 to present day, with the exception of 1943 to 1945 (war nickels were issued during this time), can be found in regular circulation. You can begin collecting Jefferson nickels simply by checking circulated nickels that you come across every day. Collectors value uncirculated Jefferson nickels (usually found supplied from banks) rarely above or below face value.
As you can see, collecting US coins is a great way to start before moving into international currency and other sorts of coins. The interesting history of the US Mint makes it captivating to learn about the various coins of the United States and its history during those times.