Depends on how you define "free." Apple says "no additional charge over your Mac Dev membership. It's included with the Mac Developer Program." I spent two entire days watching WWDC videos and digging around on developer.apple.com trying to find out how to get certificates without paying Apple the $99 for Mac Dev.

The Apple employees that I am connected to were also surprised to find out that it wasn't free outside the Mac Dev program. A former Appler helping me dig around also noted that Apple never said it'd be "free."

If you can find somewhere Apple said it would be free, I'd love to dig deeper.