Lutetium
This element is very expensive to obtain in useful quantities and therefore it has very few commercial uses. However, stable lutetium can be used as catalysts in petroleum cracking in refineries and can also be used in alkylation, hydrogenation, and polymerization applications.
glass is much more expensive as metal is retail and glass in man made
it is expensive because the metal in the drill is solid hard and the harder it is the more expensive.
PVC pipes are less expensive and easier to repair. Metal pipes are more expensive and more difficult to repair.
he used Copper {less expensive metal} for one layer and nickel {more expensive metal} for the nice shiny coating
A wooden filing cabinet can be more expensive than a metal one, however it depends on what type of wood it is. If it is mahogany or oak, it will be relatively expensive, and metal would be cheaper. However, if it is a generic pine filing cabinet, it would probably be the same price or less as a metal one.
Platinum
Yes, gold is an expensive metal.
gold is more expensive than iron simply because iron is more common and gold is also a purer metal
Metal shelves are usually at least 50% more expensive than wooden shelves. They are however more durable in many cases and take more weight. The buyer needs to decide which is better for their needs.
Rhodium is pretty rare and very expensive. More rare than platinum.
Ceramic clear is less obvious but more expensive when compared to metal. So if you can afford it or are an adult that doesn't want it to be obvious, get clear. If you are a teen, metal is more common.
Platmium is expensive because it is a type of metal.