title: Ruby - conversion string to float return 0.0
body: <p>In a variable is stored this value: <code>$10.00</code>
  And I need to get this <code>10.00</code></p>
  
  <p>I've tried to convert this value to float:</p>
  
  <pre><code>new_price = '%.2f' % (price.to_f)
  </code></pre>
  
  <p>but I get just <code>0.0</code>.</p>
  
  <p>What's wrong with that?
  I've tried also</p>
  
  <pre><code>price = price.strip
  price[0]=""
  new_price = '%.2f' % (price.to_f)
  </code></pre>
  
  <p>But even this didn't help me... where is a problem?</p>
  
  <p>Thanks</p>