I think we all appreciate the work that you guys put into this project but I have to agree that the captcha module should be free. You do not need a high volume sie to be annoyed by spam bots these days. I have a club website (under 50 members). I just put the new joomla 1.5 site live yesterday, we were using joomla 1 with CB. Overnight I have 12 new registrations. All through the CB registration module.
Great program, and its free, but if you want to keep using it and not be bothered by bot registration you will have to pay for this little add on. Sort of sounds like the drug dealer who gives out the first samples of heroin for free.
Sorry for the rant but add ons that you buy should not be to make the program functional. They should add a cool function that you want, not have to have.