IIRC they have improved the free plan over time, and even mailed users suggesting the relaxed limits might enable moving from paid to free tier [1].

I barely use my tailnet now, might have more of a case for it later, but they are near the top of my "wishing you success but please don't get acquired by a company that will ruin it" list.

[1] https://news.ycombinator.com/item?id=35615848

Even if it is, you can run Headscale on a server somewhere (or just pay).