See the $shipping in https://cgit.drupalcode.org/dc_ajax_add_cart/tree/templa...

See the $shipping in https://cgit.drupalcode.org/dc_ajax_add_cart/tree/templates/dc-ajax-shop...

You can do that creating a flag for order > $10 or < $10. And according to the flag, you can print the shipping info in the template. You will have to copy the template in your subtheme and make changes.