The cost of aluminum plate compared to steel can vary depending on various factors such as the grade, thickness, size, and market conditions. Generally, aluminum plate tends to be more expensive than steel on a per-pound basis. However, aluminum is lighter in weight and has a higher strength-to-weight ratio compared to steel, which can result in cost savings in terms of transportation, installation, and structural support requirements. Additionally, aluminum offers superior corrosion resistance, which can lead to longer service life and reduced maintenance costs in certain applications. Therefore, while aluminum plate may have a higher initial cost compared to steel, it can provide cost advantages in the long run due to its favorable properties and performance characteristics.