title: How to set Grandtotal / BaseGrandTotal with Observer?
body: <p><strong>Config.xml</strong></p>
  
  <pre><code>        &lt;sales_quote_collect_totals_before&gt;
              &lt;observers&gt;
                  &lt;discount&gt;
                      &lt;class&gt;discount/observer&lt;/class&gt;
                      &lt;method&gt;discountMethod&lt;/method&gt;
                  &lt;/discount&gt;
              &lt;/observers&gt;
          &lt;/sales_quote_collect_totals_before&gt;
  </code></pre>
  
  <hr>
  
  <p><strong>Observer.php</strong></p>
  
  <pre><code>public function discountMethod($observer)
  {
     $quote = $observer-&gt;getEvent()-&gt;getQuote();
     $quote-&gt;setGrandTotal(1);
     $quote-&gt;setBaseGrandTotal(1);
     $quote-&gt;save();
  }
  </code></pre>
  
  <hr>
  
  <p>I've already created the config.xml and Observer.php and that code doesn't work at all. $quote->getData() shows:</p>
  
  <pre><code>[grand_total] =&gt; 1
  [base_grand_total] =&gt; 1
  </code></pre>
  
  <p>But the GrandTotal on page still show the true price
  <img src="https://i.stack.imgur.com/LGRrS.png" alt="GrandTotal"></p>
  
  <p>I'm using <strong>Default Magento 1.6.2</strong> and on <strong>checkout/onepage/index</strong> the function is triggered every I clicked <strong>continue</strong> but I don't know how to set the grandTotal / BaseGrandTotal on quote.</p>