Update README.md

Cost comparison in Oracle Cloud

Author: NicolaCimitile

manageability-and-operations/observability-and-manageability/README.md

@@ -37,6 +37,7 @@ Reviewed: 10/05/2024
 - [Multi-cloud observability using OCI Monitoring](https://karthicin.medium.com/multi-cloud-observability-using-oci-monitoring-8fa87f9c5e84)
 - [How to enable OCI Observability for Golden Gate Cloud](https://medium.com/@erikasciunzi/how-to-enable-observability-for-golden-gate-cloud-06a9702c9313)
 - [How to enable OCI Observability on Oracle APEX](https://learnoci.cloud/oci-observability-for-oracle-apex-f25369bd771a)
+- [Cost comparison in Oracle Cloud](https://karthicin.medium.com/cost-comparison-in-oracle-cloud-166f4b12dcd3)
 
 ## Cloud Coaching Clinics (Videos)