I meant - smth like this:
http://contactform7.com/captcha/
ussually just 5-6 digit captcha...
Many customers do not want to use reCaptcha because they are loosing customers: it's made too hard to read (OK, less spams, but less incomes)! Even I ofter have to reenter recaptcha 2,3, sometimes - even more times! Customr after 2 tries will close Your site and go to competitors! ;-)