Update fine-tune-serverless.md

Fixing link for managing plan and costs for Azure AI Foundry

Author: RSavage2

articles/ai-foundry/how-to/fine-tune-serverless.md

@@ -263,7 +263,7 @@ When the fine-tuning job succeeds, you can deploy the custom model from the **Fi
 > day period.
 > The deletion of an inactive deployment doesn't delete or affect the underlying customized model, and the customized model can be redeployed at any time. As described in
 > Azure AI Foundry pricing, each customized (fine-tuned) model that's deployed incurs an hourly hosting cost regardless of whether completions or chat completions calls are
-> being made to the model.
+> being made to the model. To learn more about planning and managing costs with Azure AI Foundry, refer to the guidance in [Plan to manage costs for Azure AI Foundry Service](./costs-plan-manage.md).  
 
 > [!NOTE]
 > Only one deployment is permitted for a custom model. An error message is displayed if you select an already-deployed custom model.