Hello,

The first step is to enable the Traceability option in Inventory > Settings

In the Product Categories, configure the Costing method as FIFO

After this configuration, when you are doing any purchase, the system will capture the serial/lot numbers and the cost of the product will be saved for that particular set of products. 

Now you can create a Pricelist for this product. For that you can enable the Pricelist with the following configuration

Create a new Pricelist in Sales > Products > Pricelists

Do the configuration in the following way

You can add your margin and based on that, the MRP will be calculated automatically in the Sales.