Thanks for your message, Andrew. Yes - the total figure is $83 billion.
In the US, the price of blood from someone who has recovered from COVID19 is $35-$40,000 per ml (depending on the amount of antibodies).
So 4000 donations multiplied by 500ml per donation=2,000,000ml (2million) total in donations. At $35~$40,000 per ml, this comes to $70-80billion total.
You can verify here: https://www.pennlive.com/coronavirus/2020/05/money-for-blood-coronavirus-has-created-a-spike-in-the-plasma-market-as-researcher-demand-increases-report.html
I hope that helps:)

Moved my reply here.

Thanks for responding Noah. Something is not right here though. Who is making money off these samples? They're being donated aren't they?
Also, it doesn't say per ml either, it says per sample (what is the quantity of a sample?). If you research a bit, about 40-45% plasma can be extracted from 600ml whole blood. So, let's say you also get 40-45% plasma from 500ml blood. At the top end that is 225ml.
Let's do some calculations:
225ml x 4000 = 900 000 ml
900 000 x $40 000 = $36 000 000 000
That's not even half. Now take into account that only a small percentage of plasma will be viable due to various reasons such as pre-existing conditions. Then that value slides down even more.

Thanks, Andrew. As you correctly think, no one is making money off of the contribution by 4000 church members. It's a donation to aid the global effort for a cure.

Thanks for your response. The total figure is $83 billion.
In the US, the price of blood from someone who has recovered from COVID19 is $35-$40,000 per ml (depending on the amount of antibodies).
So 4000 donations multiplied by 500ml per donation=2,000,000ml (2million) total in donations. At $35~$40,000 per ml, this comes to $70-80billion total.
You can verify here: https://www.pennlive.com/coronavirus/2020/05/money-for-blood-coronavirus-has-created-a-spike-in-the-plasma-market-as-researcher-demand-increases-report.html