I clicked on Chess Mentor, then 'Start your free lessons now' and the membership thing popped up.  Are there free lessons or is it diamond members only?

diamond members.

There are a few free lessons.

i think its for trial members... http://www.chess.com/membership.html?c=icon

I think chessblood is right.  I was doing Chess Mentor for a while, but now I can't so I guess he's right.

yea those are for trials.. i recommend upgrading though if you want those.