We'll assume you already have the attribute options you need for this.

In the following example, I have an attribute called Sizes with options are  small, Medium , Large and X-Large.

  • Create matrix item using this as a matrix attribute.
  • Enter the product description, sku, cost, price and enter the price for the smallest or largest product it doesn’t matter, we will override the cost and size in the simple products in a minute.
  • Once you added things like supplier, and anything and continue
  • in the Prices Tab, select which store you want to adjust the price for the simple item by clicking on the '+' sign.

  • You will see all the simple items, to change the price of a single item, simply just double click on the simple item, after entering the correct value, save by clicking on "check-mark" icon, then "Save and Continue".
  • After making the changes, navigate to Matrix SKUs, Select the exact store that recently you have made changes on, then from the show feature select the price option, here you will see all the recent changes you made on the prices for each simple item. 

Changing the replacement/ or Average Cost

  • To change the Replacement cost for each simple item or the average cost that exist in the matrix product, you can do this by navigating to the inventory tab.
  • Once you are in the inventory, select which store you want to adjust  repl. /avg cost for a single simple item.
  • double click on the item, now you should be able to change the value, after you corrected the amount, save by clicking on "check-mark" icon, then "Save and Continue".

in addition, the price for matrix variant we were able to see the changes by navigating to Matrix SKU's. We can also do the same for cost, by doing the same process except on the "Show" Feature change the option to "Cost", please see the image below.