This is simply not true. It is FREE. Yes, there is a limitation for 2 bookable objects in FREE version and it is clearly stated. But 2 objects are well satisfactory for many users.
I just updated to the Beta release and the improvements are amazing, the new color customization tool makes it the perfect component for not only receiving but administrating your budgets in a very simple way.
About documentation I am preparing a video demo for next release: 0.7