Note: Be the Match is only available for people living in the United States.
Be the Match is a sign-up list for people who would be willing to donate life-saving bone marrow to a compatible patient. The way it works is that once you sign up, you are mailed a swab kit which you rub on the inside of your cheek and send back. Be the Match keeps your data on file, and whenever somebody needs a bone marrow transplant, they scan through their database to find compatible donors. If it's you, you get a call.
The sign-up process takes maybe an hour including the time spent mailing the package. Be the Match estimates that the entire donation process, if it ever occurs, takes 20-30 hours spread out over 4-6 weeks, including phone calls, medical appointments, and the donation itself.
Let's say the average person reading this post can make $25-$50 an hour. That means they are spending the dollar equivalent of $500-$1500 to save one life, in the event that they are called upon to donate. I'm relatively new here, but my understanding is that that's reasonably competitive. It also takes the form of hours instead of dollars, which might make it more viable for some folks (and maybe less viable for others).
You can sign up here. Happy donating!
Note: If you are 45 or older, then there is a $100 registration fee (otherwise, it's free).
Note #2: Down below, user HaukeHillebrandt has pointed out a reason why this might not be as great as it sounds, and user MichaelStJules has pointed out a similar reason (see third bullet point of the linked comment).
As I said that in my previous reply, I do agree with you that sometimes it can be very effective to improve a generally not very cost-effective intervention such as this. I also agree that one's marginal time might not be very valuable (yet not zero). So I do agree that in theory this could be a cost-effective intervention.
However, I think the marginal cost per death averted figure above of spreading this meme were overstated for two reasons:
1. Crucially, on the marginal costs:
Assume that including cognitive overhead that it takes roughly an hour for an EA to do the swap (e.g. using the swap, mailing it etc.) and the marginal value of my time on Sunday afternoon when I would otherwise just do something pointless is $10 (this is conservative see http://globalprioritiesproject.org/wp-content/uploads/2015/03/NeutralHours.pdf ).
This buys us a 1 in 800, or 0.125% chance of being a match.
This means we need to convince 800 EAs to spend $10 to find a match. The cost is $8000. In other words, your own probability of saving a life is 1 in 800 but you have to pay $10 for it.
Technically, but less crucially, we also need to add that one EA will actually have to go through the donation process for this to have an effect. 20 hours * $10 = $200. If you're unwilling to accept a 1 in 800 probability of going through the process, there'll be no benefit. For one person that means that we need to add 1 in 800 probability of paying $200 (or 25 cents). So the total for one person comes to $10.25.
We're also subsidizing expensive health care, spreading the meme that this is good, and perhaps in the process displacing more effective treatment, which can do net harm (see https://www.nice.org.uk/news/blog/carrying-nice-over-the-threshold ).
2. Also less crucially on the benefits side: As shown in the papers above the QALYs gained from might not add up to a "whole life saved", which can be seen by their measure "per additional treatment success' ("For patients at standard risk for disease, the treatment success rate was 80.3% for BMT recipients" [...] For patients with high-risk disease, the treatment success rate was 23.5% for BMT recipients"). Then, even after successful treatment, cancers often come back, which reduces the cost-effectiveness ("only 62% of patients survived the first year post-BMT, 98.5% of patients alive after 6 years survived at least another year. Almost 1/3 (31%) of the deaths in long-term survivors resulted from causes unrelated to transplantation or relapse. " see https://www.ncbi.nlm.nih.gov/pubmed/16545726 ).