Add custom text under Price

To add a custom text under price, you can use this to Custom CSS box.

div.product-price:after {
    content: "Tax included. Free shipping Australia wide";
    display: block;
    font-size: 16px;
    color: #fff;
}

Result

If you want products belong specific category will have a different text, first you can assign a tag on it. For example: Hand Craft

Next, use CSS code like this

/* price custom text */
.tag-hand-craft div.product-price:after {
    content: "Hand Craft products custom text";
    display: block;
    font-size: 16px;
    color: #fff;
}

Result