Toggle Dual Data. Added an intermediate .is-loading class.

index.html

<div class="grid">
  <div class="unit">
    <span class="js-toggle-el">$100.00</span>
    <span class="js-toggle-el is-hidden">$200.00</span>
  </div>
  <div class="unit">
    <span class="js-toggle-el">$1.00</span>
    <span class="js-toggle-el is-hidden">$2.00</span>
  </div>
  <div class="unit">
    <!-- grey btn -->
    <button class="js-toggle-trigger js-toggle-el btn btn--medium btn--inverse" id="ga-1234">Toggle 1</button>
    <!-- white btn -->
    <button class="js-toggle-trigger js-toggle-el btn btn--medium btn--secondary is-hidden" id="ga-5678">Toggle 2</button> 
  </div>
</div>

index.js

module.exports = function(){
  var triggers = document.querySelectorAll('.js-toggle-trigger');
  var els = document.querySelectorAll('.js-toggle-el');

  // toggle class .is-hidden while adding an intermediate 'disabled' attribute
  function toggle(){
    [].forEach.call(els, function(el){
      if (el.classList.contains('is-hidden')){
        el.disabled = true;
        el.classList.remove('is-hidden');
        setTimeout(function(){
          el.disabled = false;
        }, 500);
      } else {
        el.classList.add('is-hidden');
      }
    });
  }

  // Loop through triggersand add an event handler
  [].forEach.call(triggers, function(trigger){
    if (trigger.attachEvent){
      trigger.attachEvent('onclick', toggle.bind(this));
    } else {
      trigger.addEventListener('click', toggle.bind(this));
    }
  });
};