Steve_Leach1 pricing will be release at public preview launch. I know a lot of people are very eager to hear what this will be, but please stay tuned.
Emma_Kolocic for this first release, that is correct. The two primary targeted scenarios here are 1/cases where site activity correlates with - for example - quarterly/semesterly projects; or 2/cases where files would otherwise be migrated to an offline container and can now instead be migrated to a new site (e.g. archive_site_1) that is then archived. Case 2 is beneficial compared to migrating outside SharePoint because all of the security, compliace, metadata, and search remains operational. In a feature release of Microsoft 365 Archvie, we will also support file-level in-place archived to satisfy the scenario where a site has a mix of active and inactive content, and where there is limited desire to move that content into fully archivable sites.