Giving away a product for free and charging them shipping is an awesome way to make some easy sales on shopify. Watch the whole of this video and you will be ready to make free plus shipping items right away.
Watch my video tutorial below if you want to know how to set up shipping rates for free plus shipping products.
The main idea here is to make the products a certain weight so that they fall into a certain shipping category. For example 0 - 1lb could be $9.99 shipping (cost is example), then 1.5-2.5 is $19.98 shipping and so on.
The products would have to weigh 1lb or near abouts to fall into those weight categories.
Still confused after the video? Check out this blog post