ROYAL ARCHIVES
Treasure, Cost: $5
$3
Name the total amount spent during the last Buy phase of the player on your right.
If you cannot, gain a Curse and put it on top of your deck.
I assume this is referring to produced money? Either way, consider this 2P game:
"You had 6$ during your last buy phase."
"No i didn't, gain a Curse."
"What?? You had 6$!"
"Nah i hadn't."
"Of course you had"
"Nope."
"What did you have then?"
"Can't tell you, maybe you have another Royal Archives in hand."
"I.. I don't! See?"
"Dude, you can't just show me your hand!"
"I'll show you more if you don't shut up!!!"
"Fine, i had $7. Happy now? Cheater."
"You... No you hadn't...!"
"I had too."
"No!"
"Yes!"
"No!"
"Yes!"
"No"
"No"
"Yes...! D-oh!"
Edit: Sorry for repeating, i didn't pay enough attention to what scott_pilgrim wrote.