$13 lapel clip-on microphone plugs into smartphones

This lapel clip-on microphone is regularly $20, but for a limited time you can buy it on Amazon for $13 if you use the code 5PLJVX5D. I just bought one. I'll let you know how it works.

The reason I got it is that I sometimes make videos using my phone (using this great smartphone tripod mount) and the phone's built-in mic doesn't do a great job when I'm more than a few feet from the phone. I have a bunch of old iPhones, and I will use one of them with this mic plugged in it to record the audio.