Paid Cloudflare Plans include more features than a free. Some key features are: 

Free support for Cloudflare’s SSL

Web Application Firewall (WAF)

Image Optimization features called Mirage and Polish

Customization of Cloudflare error pages

The ability to create additional Page Rules can be use to do the following:

• Turn Cloudflare’s caching off on certain URLS
• URL forwarding a 301 or 302 redirect
• Extend Cloudflare’s caching capabilities.