Here are some free really easy to use captchas
visualCaptcha - The best captcha alternative
PlayThru: The Fun, Free CAPTCHA Alternative | Are You a Human
Sweet Captcha - Free Human Friendly Captcha
https://github.com/mbi/django-simple-captcha
Picatcha: Usable and Secure CAPTCHA
Ajax Fancy Captcha - jQuery plugin - WebDesignBeach.com
visualCaptcha - The best captcha alternative
PlayThru: The Fun, Free CAPTCHA Alternative | Are You a Human
Sweet Captcha - Free Human Friendly Captcha
https://github.com/mbi/django-simple-captcha
Picatcha: Usable and Secure CAPTCHA
Ajax Fancy Captcha - jQuery plugin - WebDesignBeach.com