Magento – Apply discount if 2 of the different item from a category are added

Buy X get Y free using the promo rules never produces the results you want which is why I wrote a module for it a few years ago. Have a look at my Buy X Get Y Free module, it has a Category X get Y free feature which will do exactly what you want - Buy 3 items from category 8 - add a free item to the cart.

You can see it working here - buy two or more sauces and you get free spaghetti!

This can be done through the standard Magento promotion rules.

Go to Promotions->Shopping Cart Price Rules. Fill in the relevant information for your in the first tab.

In the conditions tab click on the green plus under the rule that says:

If ALL of these conditions are TRUE

Select Products Attribute Combination in the drop down menu. This will then add the line:

If an item is FOUND  in the cart with ALL  of these conditions true:

Select the green plus again and choose SKU from the menu. Click on the ... and the enter the SKU of the first item.

Repeat this using the bottom green plus and enter your second SKU. You then should have a page that looks like:

If ALL  of these conditions are TRUE :

    If an item is FOUND  in the cart with ALL  of these conditions true:
        SKU  is  12345 

    If an item is FOUND  in the cart with ALL  of these conditions true:
        SKU  is  123456 

Finally click on actions tab and enter 10 discount amount box.

Save the rule.

You will now get 10% off your whole order if both products are present in any quantity.