If you want free then I would suggest that you take a look at Blender (http://blender.org). Blender is an open source 3D app that has a very good exporter for AE and very good Camera Tracking. There is a learning curve but there are lots of resources that will point you in the right direction.
Anything else is going to cost. If you have a 64 bit operating system upgrading AE to the current subscription will give you a lot more than just Camera Tracking. If you are just using AE to fool around then I would strongly suggest that you look into Blender and the other free compositing apps from say Black Magic Design. It would really help us give you good advice if you told us what you are trying to accomplish.