macOS Malware – What is Coupond?

I restarted my Mac, running El Capitan, and got a pop up asking whether I wanted to allow "coupond" to accept incoming network connections. I said no. I rebooted and got the message again. I have no idea what I could have downloaded.

In my Library/LaunchAgents folder, not the ~/Library folder, there is an entry for com.coupons.coupond.plist .

Then in Libary/Application Support, there is a folder for Coupons. Within it is Uninstall Coupon Printing Software.app.

I assume I got some adware/malware, but malware bytes says there is nothing amiss.

How can I safely remove this and where could I have gotten it from?