Wow, that's way worse than I would have guessed.

If your salary is $100,000 a year, and you work 40-hour weeks for roughly 50 weeks a year, that's the equivalent of $1,200.

I can't imagine spending $1,200 a year just to run my own mail server. The costs vastly outweigh the benefits. Especially considering that I'm far more likely to screw up all the rest of the security involved.