Aye, there's the rub. Cheap mic is easy - get one with a reasonably flat frequency response, then calibrate it with your soundcard to compensate for bumps and dips. A useful trick here is to use reciprocity and two identical microphones, one as the sound source and one as the receiver.
Accelerometer - tricky. The knock sensor on a car detects vibration, but it is tuned to a small frequency range. You could try building a seismic mass onto a microphone and then using that as an accelerometer.
Load cell - don't know how to do this cheap, maybe a strain gauge based system?
Cheers
Greg Locock