Supply and demand is honestly a pretty simple concept. Basically, the more something is like/bought the more expensive it'll be. Think about sneakers. Notice how most retro Jordan's that come out are at least $175 but you look at the Jordan 6 rings and they're going for $60, if that. That's because as a society we have decided that the retro Jordan's are the only Jordan's that look nice. Think about designer shoes, Balenciaga's for example. They produce so many of those shoes because people are willing to spend between $500 and $1200 on those shoes with no questions asked. Think about massages and facials. Ever wondered why they're so expensive? It's because everyone wants them, which means they also have to buy more materials to ensure the safety of each person. So the next time you're questioning why something is so expensive, ask yourself "how many people actually want/use this"?