Show Custom Content After Product Price

functions.php

<?php

function cw_change_product_price_display( $price ) {
	if(is_singular()) {
    $price .= '<small>' . ' Excl. GST' . '</small>';
    return $price;
}
	else {
		$price .= '<small>' . ' Excl. GST' . '</small>';
    return $price;
	}
}
add_filter( 'woocommerce_get_price_html', 'cw_change_product_price_display' );
add_filter( 'woocommerce_cart_item_price', 'cw_change_product_price_display' );