What makes a Comic Book, like Batman o Superman increase their value?
Certain comics will increase in value due to various reasons. The main reason is how rare the comic is compared to the number of people that are looking for it (also known as supply and demand). Since the 1980s, the comic industry has been producing an overabundance of comics making most of them relatively worthless (usually you can sell them for cover price at best). The few issues that do end up being worth lots of money nowadays are “key issues.” Key issues usually have some significant event that causes a drastic change, first appearance of a popular character, death of a popular character, etc. Other reasons that some comics have more demand is because of certain storylines that get great reviews or when a high profile artist/writer takes over a new series. Pretty much something that causes an issue to unexpectedly sell out. I don’t really know very much about DC key issues, but I can give you some examples from Marvel. Wolverine #145 is the issue where Wolverine gets his adamanti
