from: http://www.chess.com/forum/view/help-support/how-to-get-diamond-trial-for-10-days-free
It would appear that the 10 day trial is only available for those with a credit/debit card.
//You can sign up for a membership with Paypal and they will honor their 30 day money back no questions asked guarantee (as long as you cancel AND ask for a refund within 30 days.)
I want to subscribe using paypal and I got an offer of 10-day trial.
Problem is if I go to the upgrade page and I choose my plan it shows me 10-day offer and gives me no option to use paypal, just credit card.
Is there some option that I'm missing?