The trial lasts 7 days and needs no credit card. During the trial, RankScan scans every day.
When the trial ends, every page of the app leads to Account → Billing. Choose a plan there to continue. Your properties and scan data stay in place.
If nobody logs in for 30 days after the trial and no plan is active, RankScan deactivates the account. It does not delete it. See The app says that my account is deactivated.