в functions.php вставляем вот этот код
add_filter( 'woocommerce_variable_sale_price_html', 'bbloomer_variation_price_format', 10, 2 );
add_filter( 'woocommerce_variable_price_html', 'bbloomer_variation_price_format', 10, 2 );
function bbloomer_variation_price_format( $price, $product ) {
// main price
$prices = array( $product->get_variation_price( 'min', true ), $product->get_variation_price( 'max', true ) );
$price = $prices[0] !== $prices[1] ? sprintf( __( 'от %1$s', 'woocommerce' ), wc_price( $prices[0] ) ) : wc_price( $prices[0] );
// sale price
$prices = array( $product->get_variation_regular_price( 'min', true ), $product->get_variation_regular_price( 'max', true ) );
sort( $prices );
$saleprice = $prices[0] !== $prices[1] ? sprintf( __( 'от %1$s', 'woocommerce' ), wc_price( $prices[0] ) ) : wc_price( $prices[0] );
if ( $price !== $saleprice ) {
$price = '<del>' . $saleprice . '</del> <ins>' . $price . '</ins>';
}
return $price;
}