OK, tracked it down.
Seed/Cost
1/$25
2/$19
3/$13
4/$12
5/$11
6/$10
7/$8
8/$5
9/$5
10/$4
11/$4
12/$3
13/$2
14/$2
15/$1
16/$1
... and everyone gets $100 to spend.
Again, I can't run it this year, but will put together an entry if someone else wants to run it.