So you know all these sites like decaptcher dot com etc. which solve captchas for you at rates like $0.002 per captcha eh? You will quickly find that this still adds up rapidly.
What if I could tell you that you can easily cut these costs in half? Let's think a bit out of the box. Most captchas on like GMail etc. are 1 word, so it might be something like this:
This solves to 'traneaci'.
So let's take a look at another Captcha... What about... reCAPTCHA!?!?
This solves to 'ardway courts'.
Wait. Do you see the difference to the GMail captcha? It is two words instead of one. However, our captcha solving services will still solve it for us.
So what if we just exploit that and take two GMail captchas and put them into one and take the color off it so it will look like it was always one?

+
=
This solves to 'crotstess whotional'.
Will the captcha service still solve it?
Yes.
Now when you implement that into your program before accessing their API, just use Imagick or gd to glue them together and take off all saturation (i.e. double width, add one captcha on the left, one captcha on the right, change contrast, change colors).
Then split the reply at the ' ' and you have two captchas solved for the price of one
I won't supply you with the exact code for it, because I believe that is a part you should do yourself at this point, because it is the theory that matters, I won't take away your laziness
Hope you have success with it like I do!