In all seriousness, probably several tens of millions at first, then maybe more later. I'd imagine that if I were the richest person on Earth by a factor of twelve that I'd run out of things to do with my money very quickly.
I wouldn't donate, but I'd pay all of the Staff a salary, and hire paid Devs to create ACC 2.0 quickly, complete with a Bell Shop. I'd also hire full-time Staff to get other things completed in record time.
Cleverly disguised as a responsible adult ~ Cherbear
If you don't know where you are going, any road will get you there ~Carroll
Enough for temporary salaried staff, primarily developers to get ACC 2.0 up and running quickly. After 2.0 is functioning however, I think the staff positions could go back to being volunteer roles, or at least be lower paying than the revamp workers.