Help a cheapskate out. . . (bluetooth headphone question)

[episodic]

I just want a cheap mono bluetooth headset that I can pair with my cheap android phone and listen to voice based podcasts while running. I know I need the A2DP thing on the headset, and most online descriptions don't say whats what. . .

Thanks!

I'd really like to spend $20.00 or less.

Yes, I know about the nice stereo ones, I actually want a mono one so I can put it in the ear away from traffic so I have awareness of sounds around me.