My invoices say $20/yr per .com; other TLDs are more expensive. Because we have a ton of domains we spend over $20k a year with them. I'm sure there is a minimum but I don't know what it is these days.

I would not say MarkMonitor is a tool for startups. It's a tool for organizations that would lose a lot if they lost a domain. I bet Zoho wishes they could go back in time and spend $10k to avoid this problem they had.