Do you offer Free Shipping. Catch your customer's attention by customizing the Free Shipping badge on your products. Choose a contrasting color that stands out and you're good to go.
background-color: #252525!important; /*background color of badge*/
color: #FFF; /*color of text */
You can use this link http://www.w3schools.com/tags/ref_colorpicker.asp to get color codes.