Do I need a paid Cloudflare account to use SSL?

You can now use SSL with a free CloudFlare account. While CloudFlare will provide you with a free Flexible SSL, it will only encrypt connections between your visitors and CloudFlare.

It's a good idea to use Full SSL instead. You will need an SSL certificate for your domain for Full SSL to work, free SSL certificates are available from Let's Encrypt.

For more information on using SSL, please read Using SSL for higher speeds and more.