Speaking of quality of components, this is one factor that can drive xylophone prices. Most xylophones contain a large amount of wood and metal. Some woods are very expensive, as are metals, while other woods and metals can be cheap. This may be due to scarcity versus abundance or difficulty obtaining a material compared to convenience. The more rare and difficult it is to get something, the more expensive it will usually be.
At the end of the day, the person selling these instruments needs to make money, which is why xylophone prices are what they are. This is not to say that there are not good and bad deals, but if the maker is paying a lot of money for expensive components, he or she will need to mark up the price in order to make profits. This is usually why high-quality xylophones cost more.
Although the word economics is not typically coupled with the phrase xylophone prices, these two statements are actually very related. This is because prices, like the price of any good, is intricately linked to economic forces. Basically, the principles of supply and demand drive the prices of these instruments along with raw material costs.
Supply and demand are inversely related — when people want a good or service, there is less available, and vice versa. Sellers are smart enough to realize this and price accordingly. If xylophone prices are high, it's usually because people really want these instruments at that particular time and are willing to pay to acquire them. When prices are lower, it reflects a market where there is an abundance of xylophones and not as much demand to own one. Where supply and demand meet usually indicates the price on which the buyers and sellers will agree.