title: Changing HTML Value depending on checkboxes
body: <p>I want to create a price list for my graphics design website.</p>
  
  <p>Basically, I have a base price of $150 for a website design, and I want to create a module where users can check optional boxes, to add to the price. Eg:</p>
  
  <p>Price Starts from $150, which is in a total at the bottom of the page. The user can check an option upgrade costing something, I'll use $20 for the example. Once the box is checked, the total at the bottom of the page rises to $170.</p>
  
  <p>I work with programming quite a lot, but not much JavaScript. I've never done anything like this before, and wish for it to all be client-side. Where should I start?</p>
  
  <p><strong>EDIT -</strong></p>
  
  <p>Here's some HTML of the basic page I have. Upon checking the checkbox, it's value should be added to the value of what is in the text area.</p>
  
  <p><a href="http://pastie.org/private/avwkmaqztfqxma5lg6y8q" rel="nofollow">http://pastie.org/private/avwkmaqztfqxma5lg6y8q</a></p>