MonsterInsights Lite (Free)

Features:

• Dashboard Reports — See real-time stats in an easy to read report found right in the dashboard of your WordPress site.
• Universal Tracking — Your stats are never skewed thanks to the universal tracking system that’s in place. In other words, if your site visitors switch from a mobile device to a desktop, you’ll still get accurate data counts.
• Robust Pro Features — The premium version lets you track eCommerce stats, traffic sources, advertisements efforts, and you’ll have access to the MonsterInsights Forms addon, which lets you see your form conversion rates so you can make improvements and grow your business online.