WooCommerce - Custom variable price by category

<?php
  // WooCommerce - Custom variable price by category
  // code goes in functions.php for your child theme
  add_filter( 'woocommerce_variable_sale_price_html', 'custom_variable_price', 40, 2 );
  add_filter( 'woocommerce_variable_price_html',      'custom_variable_price', 40, 2 );
  function custom_variable_price( $price, $_product ) {
    $terms = get_the_terms( $_product->id, 'product_cat' );
    foreach ($terms as $term) {
      switch ($term->term_id) {
        case 20: // my category id
        case 21: // my category id, same text as category 20
          return 'From $0.80 per item';
        case 22: // some other category
          return 'From $1.20 per item';
        default:
      } // end switch
    } // end foreach
    return $price; // any other category
  } // end function