The regulation’s price tag is an estimated $2.8 billion in 2014. But EPA officials say it would save between $120 billion and $290 billion in annual health and welfare benefits the same year and help prevent up to 36,000 deaths [Darren Goode, "EPA Issues New Rule to Reduce Emissions," The Hill: E2 Wire, 2010.07.06].
The low-end estimate says we get a 4186% return on our investment in pure dollar terms, before counting in the pleasure of keeping 36,000 fellow Americans alive.
Spend $2.8 billion, save Americans $120 billion or more in health and welfare costs. Now that's money well spent!