JSFiddle - React, Tailwind, and code Playground

HTML

<form id="SSVIN" method="post">
  <fieldset>
    <legend>Engine Options
    </legend><input type="checkbox" checked="checked" required="" name="ezh"><label for="ezh">5.7L V8 HEMI 395 HP 410 lb-ft Torque - Standard
    </label>
  </fieldset>
  <fieldset>
    <legend>Functional Packages</legend>
    <div id="functionalpackages">
      <label><input type="checkbox" name="aed" value="632.00" onclick="updatetotal()">Chrome Appearance Group (Bumpers, Grille, &amp; Aluminum Wheels) - <strong>$632.00</strong></label><br>
      <label><input type="checkbox" name="adb" value="359.00" onclick="updatetotal()">Protection Group (Tow Hooks, Transfer Case &amp; Front Suspension Skid Plates) - <strong>$359.00</strong></label><br>
      <label><input type="checkbox" name="ajb" value="359.00" onclick="updatetotal()">Remote Start &amp; Security Alarm - <strong>$359.00</strong></label></div>
  </fieldset>
  <fieldset>
    <legend>Interior Options</legend>
    <div id="interioroptions">
      <input type="checkbox" id="d7x8" name="d7x8" value="41.00" onclick="updatetotal()"><label for="d7x8">40/20/40 Front Center Bench Seat - <strong>$41.00</strong></label><br>
      <input type="checkbox" id="cke" name="cke" value="100.00" onclick="updatetotal()"><label for="cke">Carpet Floor Covering - <strong>$100.00</strong></label><br>
      <input type="checkbox" id="xap" name="xap" value="114.00" onclick="updatetotal()"><label for="xap">Power Adjustable Pedals - <strong>$114.00</strong></label><br>
      <input type="checkbox" id="xhc" name="xhc" value="268.00" onclick="updatetotal()"><label for="xhc">Trailer Brake Control - <strong>$268.00</strong></label><br>
      <input type="checkbox" id="ra2" name="ra2" value="632.00" onclick="updatetotal()"><label for="ra2">Uconnect 3 with 5" Display &amp; Bluetooth - <strong>$632.00</strong></label></div>
  </fieldset>
  <fieldset>
    <legend>Exterior Options</legend>
    <div id="exterioroptions">
      <input type="checkbox" id="nfx" name="nfx"...

CSS

fieldset {
	border: solid 3px #000000;
	margin-bottom: 10px;
}

legend {
	background-color: #d3d3d3;
	border: 1.5px solid #000000;
	font-weight: bold;
	font-size: larger;
	color: #000000;
	margin: 18px;
	padding-left: 4px;
	padding-right: 4px;
}

JavaScript

function gettotalprice() {
  var fp = document.getElementById('functionalpackages');
  var fps = fp.getElementsByTagName('input');
  var io = document.getElementById('interioroptions');
  var ios = io.getElementsByTagName('input');
  var eo = document.getElementById('exterioroptions');
  var eos = eo.getElementsByTagName('input');
  var dos = document.getElementById('deleteoptions');
  var doss = dos.getElementsByTagName('input');
  var sc = document.getElementById('servicecontracts');
  var scs = sc.getElementsByTagName('input');
  var uo = document.getElementById('upfitoptions');
  var uos = uo.getElementsByTagName('input');
  var gp = document.getElementById('graphics');
  var gps = gp.getElementsByTagName('input');

  for (var i = 0, len = fps.length; i < len; i++) {
    if (fps[i].type === 'checkbox') {
      fps[i].onclick = updateTotal;
    }
  }

  for (var i = 0, len = ios.length; i < len; i++) {
    if (ios[i].type === 'checkbox') {
      ios[i].onclick = updateTotal;
    }
  }

  for (var i = 0, len = eos.length; i < len; i++) {
    if (eos[i].type === 'checkbox') {
      eos[i].onclick = updateTotal;
    }
  }

  for (var i = 0, len = doss.length; i < len; i++) {
    if (doss[i].type === 'checkbox') {
      doss[i].onclick = updateTotal;
    }
  }

  for (var i = 0, len = scs.length; i < len; i++) {
    if (scs[i].type === 'checkbox') {
      scs[i].onclick = updateTotal;
    }
  }

  for (var i = 0, len = uos.length; i < len; i++) {
    if (uos[i].type === 'checkbox') {
      uos[i].onclick = updateTotal;
    }
  }

  for (var i = 0, len = gps.length; i < len; i++) {
    if (gps[i].type === 'checkbox') {
      gps[i].onclick = updateTotal;
    }
  }
}

function updateTotal(e) {

  var form = this.form;

  var val = parseFloat(form.elements['total'].value);

  if (this.checked) {
    val += parseFloat(this.value);
  } else {
    val -= parseFloat(this.value);
  }

  form.elements['total'].value = formatDecimal(val);
}

function formatDecimal(val) {
 ...