mark Elasticsearch 7 and Elastic Stack with $$

README.md

@@ -111,7 +111,7 @@
 * [Centralized Logging with Logstash and Kibana On Ubuntu 14.04](https://www.digitalocean.com/community/tutorial_series/centralized-logging-with-logstash-and-kibana-on-ubuntu-14-04) everything you need to now when you are creating your first Elasticsearch+Logstash+Kibana instance
 * [dwyl/learn-elasticsearch](https://github.com/dwyl/learn-elasticsearch) a getting started tutorial with a pack of valuable references
 * [Make Sense of your Logs: From Zero to Hero in less than an Hour! by Britta Weber](https://www.youtube.com/watch?v=8vgTBIoF8zs) demonstrates how you can build Elasticsearch + Logstash + Kibana stack to collect and discover your data
-* [Elasticsearch 7 and Elastic Stack](https://www.manning.com/livevideo/elasticsearch-7-and-elastic-stack) - liveVideo course that teaches you to search, analyze, and visualize big data on a cluster with Elasticsearch, Logstash, Beats, Kibana, and more.
+* [$$ Elasticsearch 7 and Elastic Stack](https://www.manning.com/livevideo/elasticsearch-7-and-elastic-stack) - liveVideo course that teaches you to search, analyze, and visualize big data on a cluster with Elasticsearch, Logstash, Beats, Kibana, and more.
 
 ## Articles
 ## System configuration