Ask HN: What's the Cheapest TLD?

I am a domain/microsites junkie. I have an idea, I get a domain, and often I build a mmicrosite for it.

What are the cheapest TLD in the long run (registration + renewals), not interested in the first year deal?

If that matters NameCheap is my registrar, but willing to register somewhere else if I need to.

Thanks in advance.