Add order total in the "Place Order" button

Paste the following in functions.php:

add_filter('woocommerce_order_button_text', 'woo_custom_order_button_text');

function woo_custom_order_button_text()
{
    $cart_total = WC()->cart->total;    
    return __('Your text ' . $cart_total, 'woocommerce');
}

Change Your text by the desired text for the button.

Source: https://stackoverflow.com/questions/41930981/woocommerce-add-order-total-to-place-order-button