Looking to make a Magnetometer (ie, Gauss Meter)

I'm looking for instructions to make a magnetmeter so I can measure my speakers. I have a few hard drives in my HT setup, and I want to make sure they will be safe with new placement, especially with the center channel being right underneath them. I found the following:


But it's kind of expensive to build: $70US+

Is there a cheaper solution?

You could build that for much cheaper simply by NOT shopping at radio shack, for instance that multimeter, get the equivalent at Harbor freight, regularly on sale for $2.99 Check mouser for the sensor