The cost of raw materials is constantly changing, because many factors determine the pricing of these materials. Availability, or the amount of the raw materials left in or on Earth, affects the cost of raw materials because low availability typically means high prices. If there is a demand for a certain raw material, this can affect the price both negatively and positively. Raw materials are often graded by their purity, and this purity can affect how much the materials cost. Ease of acquisition also affects the price of materials, because easy gathering usually requires less machinery and less overhead costs.

Raw materials are constantly affected by supply, especially materials such as metals and stones that take millions of years to form. With crops, logs, food materials and other raw materials that can be grown, weather is often important for supply, because a stormy year may yield very few crops or make it difficult to raise livestock. Political unrest, rebellion and war also affect raw material supply, because workers will either make less or the materials will be offset directly to the battlefield.

Demand also affects raw materials, which often are made into products or parts. For example, if many businesses need a certain raw material for products, then demand for that material will rise. Demand can affect the cost of raw materials negatively or positively, depending on the businesses selling the materials. The popularity of these items also affects demand — if there is a popular shirt made from a certain textile, for example — then that textile's demand will increase until the shirt is no longer popular.

Most raw materials are graded based on their purity. This is determined by how many other materials are combined with the major material; for example, iron is naturally found with impurities such as carbon, magnesium and sulfur. If there are fewer impurities, the cost of the raw materials typically increases, because the materials are more valuable and manufacturers need to do less work to make them ready for product or part use. For crops, logs, food and textile raw materials, the purity metric is called quality, and it is determined by how good the material is, and perhaps the material's softness, color or taste.

Some raw materials are easy to gather, while others require large, expensive and complicated machines to gather. The ease of gathering affects the cost of raw materials, because it directly affects the overhead costs for companies. If the materials can be extracted with simple machines, then the cost will usually be lower. Materials that need educated workers and expensive machines to be collected typically will cost more.