Yes, both Circular Docs and KnowledgeBase offer a Free Trial.
Circular Docs is designed for Medium Business and Small Business.
KnowledgeBase is designed for Large Enterprises, Medium Business and Small Business.
Pricing for Circular Docs Starts at $9/Month whereas for KnowledgeBase Starts at $59/Month.
Some top alternatives to Circular Docs includes SmartSupport, HelpHub, Qualified, BetterDocs, Workvivo, KnowledgeBase, Whatis, Kbee, Docular, ProProfs Knowledge Base, Nocode and IFTTT.
Some top alternatives to KnowledgeBase includes KBPublisher, SmartSupport, KnowledgeBase Manager Pro, Omnistar Kbase, Talisma KnowledgeBase, IntelligenceBank KM, Helpjuice, KnowledgeOwl, Qualified, Workvivo, PaceKB and ProProfs Knowledge Base.