add_action( 'woocommerce_before_cart', 'blacksheep_free_shipping_cart_notice' );

function blacksheep_free_shipping_cart_notice() {

$min_amount = 50; //Ücretsiz kargo minimum limit

$current = WC()->cart->subtotal;

if ( $current < $min_amount ) {
$added_text = 'Get free shipping if you order ' . wc_price( $min_amount - $current ) . ' more!';
$return_to = wc_get_page_permalink( 'shop' );
$notice = sprintf( '<a href="%s" class="button wc-forward">%s</a> %s', esc_url( $return_to ), 'Continue Shopping', $added_text );
wc_print_notice( $notice, 'notice' );
}

}