From Yvain's 'proposal' to measure money in dead children:
According to Population Services International, a respected charity research group, it costs between $650 and $1000  to save one child's life through charity. You've probably heard lower numbers like twenty cents somewhere. The lower numbers are wrong. Yes, maybe an anti-measles vaccine for a kid in Africa only costs twenty cents, and measles can be fatal. But there's a lot of overhead, and you have to immunize a lot of people before you get the one kid otherwise destined to die of measles. I find the $650-$1000 figure much more believable. Let's round it off to $800.
So one dead child = eight hundred dollars. If you spend eight hundred dollars on a laptop, that's one African kid who died because you didn't give it to charity. Distasteful but true. Now that we know that, we can get down to the details of designing the currency itself. It should be a big gold coin, with a picture of a smiling Burmese child on the front, and a tombstone on the back. The abbreviation can be DC.
This makes sense to me, to a limited extent. You can spend money for your own benefit or to help others elsewhere, and there really are people who wouldn't have to die if you would forgo some luxuries. Making this tradeoff more explicit ("we're looking for an apartment costing no more than six dead children annually") might lead some people to greater generosity. It's a way of abstracting compassion.
Two things worry me, though. The first is that there's a big focus on spending here , but increasing earnings deserves more focus: getting a raise or a new job that added $10K to my salary would let me keep more children from dying than would reducing my spending on myself to zero.  The second is that thinking of all your purchases in terms of dead children is likely to make you miserable. Not just that, but miserable to little gain: you still probably spend almost as much money on yourself, you just feel more guilty about it. Much better, I think, is to pick a rule for how much to give and then apply it to money as it comes in. That way each purchase has no effect on the number of deaths you're averting.
(Note: I also posted this on my blog)
 The current number is probably closer to $2K.
 Maybe this is because it sounds weird to talk about salary in terms of dead children? ("I wonder what job earns me the most dead children?") Perhaps for earning the unit should be the "undead child"?
 In 2011 Julia and I lived on $18K for the two of us, not including taxes or health insurance.