Yes, both Flow and Notion offer a Free Trial.
Flow is designed for Large Enterprises, Medium Business and Small Business.
Notion is designed for Individuals, Freelancers, Medium Business and Small Business.
Pricing for Flow Starts at $6/User/Month when Billed Yearly whereas for Notion Starts at $4/Month when Billed Yearly.
Some top alternatives to Flow includes Smartsheet, Miro, Process Street, Wrike, Notion, TeamGantt, Teamwork, ProjectManager.com, Microsoft Project, ProWorkflow, Trackboard, TaskBranch, Quick Base, ClickUp, Height, Task Flow and Project Insight.
Some top alternatives to Notion includes Jira, Knote, Trello, Confluence, Asana, Easynote, ClickUp, TWiki, MeisterNote and Zenkit Hypernotes.