There isn't one at the moment. I removed it about two months ago as an attempt to encourage more signups.

But then you dont get data about how much someone is willing to pay. Why not at least have your pricing table and underneath each pricing package, a signup for free call to action button with their own href anchor ( /signup#gold ) to track within google anyltics or something? This way even though people so sign up for free you'll gain a bit of knowledge about which package they clicked on and as a side effect the potential intend. Not perfect but better then no metrics.

Not to mention you're probably turning away signups that think a completely free API is too good to be true. Check out the first question of the Van Westendorp test: http://en.wikipedia.org/wiki/Van_Westendorps_Price_Sensitivi...

link should be (http://en.wikipedia.org/wiki/Van_Westendorps_Price_Sensitivi...)