And, is there any case where you don't want to gain the Curse first?
I played Outpost. I want my three card outpost hand to be X/X/Y and the top card of my deck to be Curse, for whatever reason. X is Embargoed and costs 4, Y costs 5. I have Talisman in play and Watchtower in hand, $9 and two buys. To get my hand and deck I want, I need to buy X first, triggering Talisman and Embargo on buy effects, and have Embargo happen first so I can topdeck the Curse underneath the talismaned X, the bought X, and the Y I buy in a second.
EDIT: Just realized I did the opposite of what you asked. Pretend I said you want your Outpost turn to be X/Y/Curse, and X on top of the deck.