If I cancel my Wcart subscription, does my store close straight away?

No. Cancelling stops future renewals, but your store keeps running until the end of the period you have already paid for.

1. Go to Settings → Account → Subscription.
2. Click Cancel subscription at the top right.
3. Confirm with Yes, cancel.

The banner then shows Cancelled and the date your plan stays active until. You won't be charged again.

If you change your mind, choose a plan under Upgrade / change plan before that date to keep your store live. There is no cancel button during a trial, a free period or on a free plan, because there is nothing to renew.