Can I display reduced prices to customers who arrive at our website via a specific URL?

Hi,

We’d like to be able to offer early access to our sales to email subscribers. We don’t want them to have to sign in with their email address to be able to view the sale prices. Is it possible to display reduced prices to customers who arrive at our website via a specific URL? Would an app be required? If so, could anyone recommend a good app for this please?

Thank you.