This what I found on registering:

You get 10 free captures on signup.

After that, plans vary from '$5 for 100 captures' to '$30 for 1000 captures'.

[edit #1]

I added this to one of my websites. Holy Shit, it is good! I've bought 100 captures for now, for $5.

[I shamefully admit that this is one of the ideas I had but didn't execute all. These guys have done an amazing job.]

[edit #2]

Thanks to paraschopra's comment, I checked out userfly too. I am going to try that too. Clixpy didn't detect keystrokes correctly on one of my websites. Lemme see how userfly fares for the same test case.

  Note to self : Competition is good. 
  ------------

It is like a neighborhood coffee shop getting more traffic because of a Starbucks opening nearby, contrary to the tiny shop's fears. I wouldn't have become a user of userfly today without clixpy.

[edit #3]

( Userfly dude rambles for quite a while in the demo :-) )

Notes on Userfly:

Userfly's performance can be better. Hmm. Definitely. But I like it too.

I wish Google released a product that has this functionality. I don't trust userfly or clixpy completely, since they didn't replay my test drive properly. But I'll definitely be using them until something more robust comes along.