We run with a Pay What Feels Good pricing policy.
The Shopify app store isn't designed for a fluid, discussion-driven pricing policy; instead, it's designed for predefined, static pricing tiers. So, we use that tier structure in the app store to present the suggested prices available for each Shopify plan. This has the side-effect of having Shopify present the smallest suggested figure as the "starting at" price for Mechanic, which is not an accurate description of how any of this works. :)
If you've got questions, you are always invited to reach out, at [email protected].