Nady 401X Quad Wireless 4-Channel Headset + Lapel/Lavalier Microphone System – 8 Microphone Bundle (HM-3 + LM-14)

It's simple and works well. I suspect those who have had problems might have placed the 9V battery in backwards, which is not only possible, but very easy to do. The positive terminal indicator is molded in the same plastic as the housing, so it is hard to see, and the only differentiator from the negative terminal is a 1mm square T-shape.

Good microphone system for the price. The headset mics are terrible however, the lapels on the other hand are actually pretty good. I used these for a play at my church and they performed better than I expected.

works just like is should.