Could you explain here how the new merchant works?
Merchant maintains a stock of cards (how many it owns), a starting value is the difference of how many it sold and bought while the old merchant was working.
- If stock<=0, merchant doesn't sell that card, only buys, and the prize for the card rises over time until next transaction.
- If 0<stock<100, merchant both sells and buys the card, prize for the card lowers over time until next transaction,
- If 100<=stock, merchant doesn't buy that card, only sells, and the prize for the card lowers over time until next transaction.
After each transaction, the price of a card is increased/decreased (depending if it was buy or sell transaction) by 10%.
For the purposes of merchant, all card types and variants are equal, with only one exception. Merchant will always buy a foil version of a card, even if it has full stock of the card, and foil card price is always double the normal card value.
You can have a maximum of 255 of a single card, so there should be no problem with owning more than 4 of it. I don't see any value in "destroying" cards.