The thing that is actually confusing is BM + Crown + BM. Which cards do you get to look at...?
- play Black Market1
-- reveal 3 cards from the BM deck
-- play Crown
-- -- play Black Market2
-- -- -- reveal the next 3 cards from the BM deck, may play Treasures and buy one of those 3
-- -- play Black Market2 a second time
-- -- -- reveal the next 3 cards from the BM deck, may play Treasures and buy one of those 3
-- play any other Treasures you want, may buy one of the originally revealed 3
Once the cards are revealed from the deck, they're not on the deck any more, so subsequent plays of Black Market just look at the deck and know nothing about the cards currently revealed.
It reminds me a little of Lookout+Cultist; you look at 3 cards from your deck with Lookout, if you trash a Cultist, you draw the next 3 cards of your deck, while the other 2 cards you're currently looking at are not part of your deck.