If I remember correctly, infant mortality rate in sub-Saharan Africa is around 10%; by way of contrast with that of ~ 1% in the United States. I think (but am not sure) that the bulk of this difference is due to vaccinations. I can dig up a citation if you'd like me to.
Even if the 10% infant mortality remained with vaccinations, in absence of evidence to the contrary one should expect that saving ten infants will allow nine of them to live past infancy.
According to GiveWell's page on standard of living in the developing world sub-Saharan Africans have about a 50% chance of living to age 65.
Eyeballing this GiveWell graph gives sub-Saharan Africans about a 50% chance of living to age 50. I suspect dodgy statistics.
I've run in to the argument that cryonics beats VillageReach on a simple "shut up and multiply" level, by assuming an infinity vs finite tradeoff. Having read the Fun Theory sequences, it struck me that this wasn't a reasonable assumption, so I sat down, re-read a few relevant posts, shut up, and multiplied.
In Continuous Improvement, Eliezer ballparks a good fun-theory life as having a maximum length of around 28,000 years. In Robin Hanson's Cryonics Probability Breakdown, he assigns cryonics a conjoint probability of about 6%. 28,000 * 0.06 gives us a net return of 1,680 expected years.
Full body suspension from the Cryonics Institute currently costs $28,000.
VillageReach, according to GiveWell, can save an infant's life for less than $1,000.
For the price of Cryonics, we thus save 28 lives. 1680 expected years, divided by 28, puts the break-even point at an average lifespan of 60 years for those infants saved. A quick peak at Wikipedia suggests that the average African life is under 60 years for the majority of the continent, although there are some important nuances to really get a full picture.
Obviously, these are rough numbers, and I doubt many people base their decisions solely on "years lived". I do find it rather interesting that cryonics is currently about on par with one of the most effective charities in the world on that metric, however :)