The Ramsey Electronics TFM-3, Trifield EMF Meter is the most inexpensive tri-field meter on the market, but there is a catch. You have to put it together yourself!!! This  unit is available from Ramsey Electronics as a project kit and requires some skill and patience with a soldering iron. This is not a meter for the beginner and is an extremely sensitive meter. It has a ground plate that your finger must touch when holding and using this meter. It has the capability of detecting the energy from a living being. It has 3 settings, RF (radio frequency), Electric and Magnetic. It also has a zero adjust knob for calibrating the unit based off the setting. The manual says it can take 6 hours to assemble this kit if you are a beginner. I saw this meter being used by TAPS in an episode of Ghost Hunters and was amazed when I found it online at Ramsey Electronics. There is no audio sensor and it does not give an exact unit of measurement, but is worth every penny! This kit retails for about $65.00 USD.