Should i offer free shipping on shopify

If it shows on the variant section, while editing the product info, how much the total cost will be for me, which includes the wholesale price, taxes, and shipping cost, and i price my products by that total price, should i then offer free shipping on all the products i add to my store? in a sense, I'm adding the shipping cost into my price so would it would be more cost efficient to offer free shipping? Or should i just make some promo such as: free shipping if you spend 25$ or more?