title: Most efficient way to convert a string to 2 decimal places in C#
body: <p>I have a <code>string</code> which needs a decimal place inserted to give a precision of 2.</p>
  
  <pre><code>3000 =&gt; 30.00
   300 =&gt;  3.00
    30 =&gt;   .30
  </code></pre>