Thank you for your feedback. I'm thinking of the paid version. I would like to offer it much cheaper than balsamiq, probably. Additionally, we'll be offering strong discounts for early users.
Follow what Affinity did (cheap and one-time) and you'll sell to a lot of people like me who would otherwise give it a miss. Save your subscription tiers for businesses needing more collaboration, SSO, etc.
With that strategy as well you'll build brand awareness which will probably ultimately lead to more sales as those solo devs advocate for its use in teams in their day jobs.