Tradingsim offer a free 7-day trial on new accounts, without a credit card.  Once your free trial is complete, payment will be required to continue using Tradingsim.

What If I cancel my account after I make a payment?
Once you cancel you won’t be charged again; however, all payments made are non-refundable and we do not offer pro-rated refunds

How do I cancel my account?
You can cancel your account at any time by logging into the Tradingsim application and selecting the “My Account” link. Once you are on the My Account page, click on the “Manage your Account” button and select the option to cancel your account