(Render employee) Our free tier is actually quite constrained (e.g. your apps go to sleep if they're not getting traffic, builds are slower, etc). But if it works for you, great!
I was expecting that because that's what Heroku does, but I don't see anything about it on the pricing page (even in the fine print). So either it's a great deal, or highly deceptive marketing
Edit: Argh, you have to click a [?] and then click through to another page where they explain that. I think they've lost my business; that's sketchy as hell.
If that had just been up-front on the main pricing page I would have become a (small) paying customer, buying the $7 plan and moving off of Heroku. But now Render has lost my trust, so I've deleted my account.
IMO, all the limitations of each one of these $0 plans should be up-front on the big, main card. You have some limitations listed there - "100 GB/month bandwidth included", "SSD disks for $0.25/GB per month", "1 GB SSD storage included", etc - which implies to the reader that those are all of the limitations. But then, the most important limitation in each case gets buried. That's what feels intentionally deceptive.
Your point around the limitations is well articulated and valid. The last thing we want is to be deceptive, even unintentionally.