I want to enable a discount that says buy a product on MRP and get same product for free

[Jhandooz]

Hi there, 

I have already given some discount on all my products. But I want a discount code which says if a person buys a product on MRP, then the person would get the same product for free. How can I create such offer?

[Jhandooz]

Here is my store url - https://jhandooz.myshopify.com/