There are two different types of comic book buyers - investors and collectors. The reason for buying comic books depends on how you use them. If you really like comics and collect your favorite ones, then you could be termed a collector. A collector of comic books can have a large or small collection and carefully chooses which ones he/she buys. Some of the collections are extensive and the collector has them to look at every now and then or to show to others. A collector carefully preserves the comic books and many of the titles have sentimental values, such as the first one ever read or a favorite superhero.
The comic book buyers that fall into the investor category are purely in the business to make money. They look at the current value of a comic book before they buy hoping that the value. This sort of buying is similar to playing the stock market. You gather an extensive collection so that when the price is right you can sell it and make a lot of money. Many people look on their collections of comic books as a sort of retirement fund that they can sell when the time is right and have the money they need for travel or to retire in the country.
Many comic book buyers make a living out of buying and selling comics. Although they do not keep the comics as type of investment, they do invest money into setting up a business, either online or off, where they sell comic books to collectors and investors. The comic book business could be their main line of work or a part time job. These comic book buyers search for titles that they believe are going to rise in value, hold onto them until they do and them sell them for a tidy profit.