Well, it's mostly about calculating P-Stone's value and just adding 10 from Ventures.
And this depends on Black Market which you can make as wild as you want.
P2 also happily Ambassadors everything he has back to the supply of course, at which point his Ambassador is trashed and gained by P1 with Rogue/Graverobber.
So:
BM = 30 cards
7 Colonies, 7 Provinces, 7 Duchies, 7 + 3 + 3 Estates = 34 cards
14 Platinums, 29 Golds, 39 Silvers, 59 + 7 + 7 Coppers, 14 Potions = 169 cards
10 * 9 + 9 (bane) + 10 extra Rats = 109 Kingdom cards
9 Curses, 9 Ruins, 10 Spoils, 10 Madmen, 10 Mercenaries (not in Supply doesn't count toward empty piles), 5 Tournament Prizes = 53 cards
Add 2 cards to empty 2 piles.
Grand total: 397 cards
We've got 5 in hand, drawing a 6th (Venture), playing 10 more cards from our deck (9 Ventures, 1 PS) so we have 381 cards in deck and discard, making the PStone worth 76, adding $10 from Ventures gives us
...$86
I don't understand how you get to $108.