What happens to my properties if I move to a smaller plan?
They are kept. Properties beyond the plan limit are archived rather than deleted, and you can restore them.
Your properties are kept. Nothing you have entered is deleted because a plan changed.
Cloud Free caps how many properties can be PUBLISHED, not how many you may have. If you move to a plan with a lower limit than the number you have published, the most recently published ones beyond the limit stop being shown on your site and are archived. They stay in your account, with their photographs and their text, and you can bring any of them back with Restore. A restored listing returns as a draft, so you publish it again yourself, within what your plan allows.
The same is true of your pages and your published site: moving between plans changes what is shown, never what you have written.
The owner of the account changes or ends a paid plan with Manage billing, under Billing in the console; see "How much does Housing Market Cloud cost?". This describes what happens to your properties when a plan becomes smaller.