title: PHP Currency Regular Expression
body: <p>I am trying to find a piece of regex to match a currency value.</p>
  
  <p>I would like to match only numbers and 1 decimal point ie</p>
  
  <p><strong>Allowed</strong></p>
  
  <ul>
  <li>10</li>
  <li>100</li>
  <li>100.00</li>
  </ul>
  
  <p><strong>Not Allowed</strong></p>
  
  <ul>
  <li>Alpha Characters</li>
  <li>100,00</li>
  <li>+/- 100</li>
  </ul>
  
  <p>I have search and tried quite a few without any luck.</p>
  
  <p>Hope you can advise</p>