Yes, both Nuclino and Slab offer a Free Trial.
Nuclino is designed for Large Enterprises, Medium Business and Small Business.
Slab is designed for Medium Business and Small Business.
Pricing for Nuclino Starts at $5/User/Month when Billed Yearly whereas for Slab Starts at $35/Month when Billed Yearly.
Some top alternatives to Nuclino includes Trello, Confluence, CollaborateCloud, Airtable, ClickUp, Microsoft SharePoint, Collabee, Slab, Notion, Slite and Witeboard.
Some top alternatives to Slab includes Archbee, GitBook, Zoho Wiki, Drupal Wiki, LearnLode Enterprise, Matterial, TWiki, Wiki Valley, GoGoWorx and Kbee.