Microsoft has SQL Server Health monitoring tool, which I have noticed that many of us do not give it a try. Microsoft has released Monitoring management pack download recently and it does plenty of the task, which normally one would like to do. Instead of going for third party tool, I suggest you give it a try.
Following text is produced directly from original MSDN page from here.
The SQL Server Management Pack provides the capabilities for Operations Manager 2007 SP1 and R2 to discover SQL Server 2005, 2008, and 2008 R2. It monitors SQL Server components such as database engine instances, databases, and SQL Server agents.
The monitoring provided by this management pack includes performance, availability, and configuration monitoring, performance data collection, and default thresholds. You can integrate the monitoring of SQL Server components into your service-oriented monitoring scenarios.
In addition to health monitoring capabilities, this management pack includes dashboard views, extensive knowledge with embedded inline tasks, and views that enable near real-time diagnosis and resolution of detected issues.
Reference: Pinal Dave (https://blog.sqlauthority.com)