Based on some CAPTCHA solving sites it costs about $3 per 1000 ReCAPTCHAs solved. That shows you how worthless adding ReCAPTCHA to your site is. All it'll do is slow bots down a bit and cost $0.003.

Here's an extension to use those services in the browser so you never have to solve one again: https://addons.mozilla.org/en-US/firefox/addon/recaptcha-sol...

That's assuming you can't get Buster to work.