JSFiddle - React, Tailwind, and code Playground

HTML

<form id="cartForm" method="post" action="/cart.html">
<div class="prod-details">
<div class="prod-name">PC 1000</div>
<div class="prod-code">pc1000</div>
    <div class="prod-price">$<span class="base-price">450.00</span></div>
<p>Customize your PC, We'll update your system price as you make your selections.</p>
<div class="prod-attributes">
<table>
<tr>
<td><input type="radio" value="Win8" name="os" data-price="0" id="Win8" checked /> Window 8 [included in price]</td>
<td><input type="radio" value="Win8.1" name="os" data-price="100" id="Win81" /> Window 8.1 [Add 100]</td>
<td><input type="radio" value="Winpro8.1" name="os" data-price="160" id="Winpro81" /> Window 8.1 Pro [Add 160]</td>
</tr>
<tr>
<td><input type="radio" value="4gb" name="ram" id="r4GB" data-price="0" checked /> 4GB [included in price]</td>
<td><input type="radio" value="8gb" name="ram" id="r8GB" data-price="40" /> 8GB [Add 40]</td>
<td><input type="radio" value="12gb" name="ram" id="r12GB" data-price="70" /> 12GB [Add 70]</td>
</tr>
  <tr>
      <td>
    <select id="os1" name="os1">
  <option value="Win8" data-price="0" id="Win8" selected>Window 8 [included in price]</option>
  <option value="Win8.1" data-price="100" id="Win81">Window 8.1 [Add 100]</option>
  <option value="Winpro 8.1" data-price="160" id="Winpro81"> Window 8.1 Pro [Add 160]</option>
</select> 
      </td>
    </tr>
</table>
</div>
</form>
<div id="rTotal">450.00</div>

JavaScript

$("[name=os],[name=ram],[name=os1]").change(function(){
    $("#rTotal").html(parseInt($(".base-price").html()) + parseInt($("[name=os]:checked").data("price"))+parseInt($("[name=ram]:checked").data("price"))+parseInt($("[name=os1] :selected").data("price")))
    
})