FWIW, this is usually called buying either "life insurance" or a "life annuity," depending on whether you want to take a short or long position. The underwriters of such bets tend to be reticent about offering them to 3rd parties, though, for what are probably obvious reasons.
Not really a counterpoint, but interestingly there used to be a fairly widespread practice of corporations buying life insurance for low level employees. It was often called "Dead Peasant Insurance", and when the employee died the corporation benefited.
It never made an iota of economic sense -- if insurance underwriters are on the wrong end of that deal, they aren't doing their jobs very well -- but a number of large corporations would do it, and gleefully pocket the payouts when rank and file employees died.
Are you sure you’d like random people putting a price on your head?
A sufficiently liquid prediction market on a human life is indistinguishable from a bounty. That’s exactly why you can only take out life insurance if you have some reasonable financial stake in somebody staying alive and not the opposite.
