I was eager to give Render.com a try, but $20/user seems both strange and unnecessary - especially considering your positioning as an alternative to Heroku (you even have "Compare to Heroku" on your frontpage). For our case, if we were to switch over from Heroku, we would be paying more for _just the users_ than we do in total for everything at Heroku.
I'd be really interested in hearing why your reasoning for seat-based pricing, as I struggle to see this from a user perspective, and from the perspective as someone who runs a SaaS. Paying a $20/month premium per user just for the privilege of paying you for computing seems like a strange proposal.