If you want to cancel your trial, you can do so from the Account section. After logging into your Polkadot Tiger account, navigate to the settings in the top right corner. After clicking it, select the Account option.

Here, on the right side of the screen, you can see your current plan. Below details of your plan, you see the ‘Cancel subscription’ option. By clicking it, you will be taken to the page summarizing your billing information. Click on the Cancel plan button in the Current Plan section to complete the cancellation. 

Make sure that you do the cancellation within the 14 day period though because after that your account will be charged by the full price of your selected plan.

After your trial expires and you are transferred to the full plan, you can cancel any time as well. The process is the same as for the trial period.