Many of the best keyboard chord tutorials are not only free, but available instantly on the internet. I know Jermaine has many, as does my friend Dave, and I have at least 100 -- probably more like 200 by now.
Here are a few:
Major chord tutorial
Minor chord tutorial
7th chords tutorial
There are lots more, but that will suffice to get someone started. Then they can sign up for an entire series of piano lesson tutorials on chords and chord progressions.