I am new to the site...and how do you identify the free vs. pay applications?
Splunk currently charges for the following apps:
There are other vendors posting to Splunk Apps, with both free and paid products. They might have product pages on their own sites. See http://www.tenable.com/blog/pvs-app-for-splunk for one example, or http://sideviewapps.com/apps/sideview-utils/ for another. Both of these vendors have listings on Splunk Apps. There are others, too.
Thanks to both of you for answering. One follow on. Are there any other sites,locations or vendors posting free or pay add ons for splunk?
The vast majority on apps.splunk.com are free. You can probably count on one hand the number that require payment. Just download the ones you want and install them, and then see which ones "just work," and which ones require you to pay something to acquire a license key so that they work.
Splunk's "Enterprise Security" app is one that requires a license key to work. Most of the others will "just work."