Yes, both TribalBase and Tettra offer a Free Trial.
TribalBase is designed for Large Enterprises, Medium Business and Small Business.
Tettra is designed for Large Enterprises, Medium Business and Small Business.
Pricing for TribalBase Starts at $29/Month whereas for Tettra Starts at $8.33/User/Month when Billed Yearly.
Some top alternatives to TribalBase includes Troopr, Tettra, Qualified, Workvivo, Socialtribes, Talkai, TribePulse, Tribe, OneBar and IFTTT.
Some top alternatives to Tettra includes Zoho Wiki, KBPublisher, Drupal Wiki, TWiki, KnowledgeBase Manager Pro, Omnistar Kbase, Talisma KnowledgeBase, KnowledgeOwl, KnowledgeBase and ProProfs Knowledge Base.
