It should be a full citation based on what's found in the index (you certainly don't need to buy any records!) There are a couple of examples for Scotland's People on the Tartan Trail page:
Example Citations Specific to Scotland
"Church of Scotland: Old Parish Registers - Banns and Marriages" database, National Records of Scotland, ScotlandsPeople (https://www.scotlandspeople.gov.uk/: accessed 27 May 2020), John Dove and Isobel Simson, 28 October 1732, Leuchars; citing Parish Number 445, Reference Number: 10 358.
[http://www.scotlandspeople.gov.uk ''Scotland Census, 1881''] > County: Dunbarton > District: Bonhill > Adam Kennedy > Reference: 593/ 9/ 7; National Records of Scotland, 3 West Register Street, New Register House, Edinburgh, EH1 3YT.
Those provide the reference data that we'd need to find the record again. Does that help?