HTTP/1.1 200 OK
Content-Type: application/xml; charset=utf-8
ETag: "a81253e90a4f16089b951028675c58d2"

<?xml version="1.0" encoding="UTF-8"?>
<add_on href="https://api.recurly.com/v2/plans/gold/add_ons/ipaddresses">
  <plan href="https://api.recurly.com/v2/plans/gold"/>
  <add_on_code>ipaddresses</add_on_code>
  <name>IP Addresses</name>
  <display_quantity_on_hosted_page type="boolean">false</display_quantity_on_hosted_page>
  <default_quantity type="integer">1</default_quantity>
  <unit_amount_in_cents>
    <USD type="integer">200</USD>
  </unit_amount_in_cents>
  <measured_unit_id>123456</measured_unit_id>
  <add_on_type>usage</add_on_type>
  <usage_type>price</usage_type>
  <created_at type="datetime">2011-06-28T12:34:56Z</created_at>
</add_on>