CISCO
Yes, both HelpHub and ProProfs Knowledge Base offer a Free Trial.
HelpHub is designed for Medium Business and Small Business.
ProProfs Knowledge Base is designed for Large Enterprises, Medium Business and Small Business.
Pricing for HelpHub Starts at $39/Month when Billed Yearly whereas for ProProfs Knowledge Base Starts at $0.30/Month when Billed Yearly.
Some top alternatives to HelpHub includes Zendesk Support, Zoho Desk, Tidio Helpdesk, Freshservice, Freshdesk, Teamwork Desk, Support Hub, Motadata HelpDesk, HelpDesk, SysAid, Jitbit Helpdesk, Desky, LabiDesk, HESK, Helpjuice and KnowledgeBase.
Some top alternatives to ProProfs Knowledge Base includes KBPublisher, SmartSupport, Talisma KnowledgeBase, HelpHub, KnowledgeOwl, Qualified, Workvivo, PaceKB, KnowledgeBase, Whatis, IFTTT and StructHub.