What is the cheapest alternative to the Retrospective Software Tool Parabol?

Depending on the size of your team, Echometer is the more affordable alternative to the retrospective software tool Parabol. Parabol charges $8 per team member, while Echometer charges per team. Since Echometer costs $29 per month for a full team, Echometer is more affordable if you have more than 3 team members - which is the case for most teams.