How do I activate my free trial?

You have to give them your credit card details for the free trial to begin. After the trial your card is billed unless you choose to opt out.

They also have a paypal option. It's next to the little pictures of credit cards.

In the sign up page, you can choose paypal as "payment option". This will charge the money from your account, but you can get your money back before the end of the 30 days with no questions asked as it says, that's how your trial works.

EDIT: Actually I'm pretty sure I saw a "10 day free trial" option before. I tried the site search, but couldn't get anywhere. It seems they don't have that any more, and have this 30 days money back guarantee option instead. Still maybe you should wait for an answer from staff.