Monoprice 2.4GHz 2-Way Wireless Microphone System $19.99 Free Shipping
Looks like it is probably the same thing as this MOVO mic that has a lot more reviews on Amazon.
A few samples can be found by searching YouTube. Of course, you would be better off with something else if you are a video professional, but looks like it might be a nice item for hobby use or small business social media needs.
2.4GHz 2-Way Wireless Microphone System (with Hip Clips & Camera Mount)
Enjoy the benefits of hands-free, wireless, two-way communications using this Wireless Microphone System from Monoprice.
This 2.4GHz wireless communications system is designed for professional videography and personal communications applications. In a videography scenario, it allows you to record audio from the on-camera talent and to give audio cues to the talent to distances up to 150 feet, without those cues being recorded.
The microphones at both end are "always on", so it is also perfect for hands-free, two-way personal communications. This makes it well suited for use by busy professionals who need to be in constant contact on the job, such as stage hands, security personnel, restaurant staff, and event coordinators.
The receiver and transmitter are each powered using two AA batteries (not included). The transmitter features a belt-clip, while the receiver includes both a belt-clip and a cold-shoe mounting option.
2.4GHz wireless two-way communications system
Only audio from the transmitter is recorded, allowing the camera operator or producer to give live audio cues to the on-screen talent without those cues included in the recorded audio feed
Lavalier microphone includes foam windscreen/pop filter and lapel clip
Microphones are "always on", allowing for hands-free communications
Receiver includes both cold-shoe and belt-clip mounting options
Receiver and transmitter are paired at the factory, so no additional pairing is required
150 foot actual range in clear air