/home/brandsfa/www/vendor/mercadopago/dx-php/samples/checkout-buttons/basic-preference/button.php
<?php

    # Crear un boton de pago a partir de una preferencia con atributos requeridos minimos

    require_once dirname(__FILE__).'/../../index.php';

    $preference = new MercadoPago\Preference();

    # Building an item

    $item = new MercadoPago\Item();
    $item->id = "00001";
    $item->title = "item"; 
    $item->quantity = 1;
    $item->unit_price = 100;

    $preference->items = array($item);

    $preference->save(); # Save the preference and send the HTTP Request to create

    # Return the HTML code for button

    echo "<a href='$preference->sandbox_init_point'> Pagar </a>";

?>