The Amazon API returns the response in XML format with the ItemAttributes node containing the bulk of the information about the product including the title, author’s name, list price, physical dimensions and so on.

<Item>
  <ASIN>B000A2XB9U</ASIN>
  <ItemAttributes>
    <Title>Rockin' the Corps</Title>
    <UPC>014381273229</UPC>
    <ListPrice>
      <Amount>1999</Amount>
      <CurrencyCode>USD</CurrencyCode>
      <FormattedPrice>$19.99</FormattedPrice>
    </ListPrice>
  </ItemAttributes>
</Item>

The XMLService of Google Apps Script can be used to parse the response group as shown below:

function parseAmazonXML(xml) {
  var obj = {};
  var xmlData = XmlService.parse(xml);

  var element = xmlData.getElement();
  var items = element.getElement('Items').getElements('Item');

  for (var i = 0; i < item.length; i++) {
    if (items[i].getElement('ItemAttributes')) {
      var title = items[i].getElement('ItemAttributes').getElement('Title').getText();

      if (items[i].getElement('ItemAttributes').getElement('ListPrice')) {
        if (items[i].getElement('ItemAttributes').getElement('ListPrice').getElement('Amount')) {
          obj[title] = items[i].getElement('ItemAttributes').getElement('ListPrice').getElement('Amount').getText();
        }
      }
    }
  }

  Logger.log(obj);
}