"Actual cost" is the most commonly used term to refer to the real cost of something in Engpsh.

The actual cost includes all the expenses that were incurred to produce or acquire a product or service, including materials, labor, and overhead.

Example sentences:

The actual cost of the project was significantly higher than the original budget.
We need to calculate the actual cost of each product to determine the price.
The actual cost of producing this product is much lower than we initially estimated.

中文翻译：

这个项目的实际成本比最初预算高得多。
我们需要计算每个产品的实际成本，以确定价格。
生产这个产品的实际成本比我们最初估计的要低得多。