1. Output: The global output of palm oil is relatively high, and the cost of planting palm trees is relatively low. In contrast, the global soybean oil production is relatively low, and the cost of planting soybeans is also high.

2. Uses: Palm oil has a wide range of uses, including food processing, edible oil, biofuels, etc., so the demand is relatively large. In contrast, soybean oil is mainly used in food processing and edible oil, and the demand is relatively small.

To sum up, palm oil is usually cheaper than soybean oil because palm oil has high yield, low planting cost and wide application, while soybean oil has low yield, high planting cost and relatively few applications.