The problem with using cheaper materials is that it will be difficult to find enough documentation and tutorial on using them.
I have been through these tutorials for the connections and code.
For bluetooth mate :
http://www.sparkfun.com/tutorials/264
For IMU :
http://bildr.org/2012/03/stable-orientation-digital-imu-6dof-arduino/
http://www.varesano.net/blog/fabio/my-first-6-dof-imu-sensors-fusion-implementation-adxl345-itg3200-arduino-and-processing
I will probably modify and build upon the code given in these tutorials.