I understand, I am not meaning at all to change the promo codes, it's just that when someone receives a promo code for a starter pack, it's as if they purchased one save for how those 30 cards are treated. They have no option to then purchase one for $10. (Yes, they can purchase singles but most people who entered to win a free starter are generally those who didn't want to invest quite yet -- and don't feel they have any need to purchase single cards yet)

steemmonsters.club can't see that they have any cards if they only have those 30 starters, unfortunately. The player who used the promo code doesn't realise this, and would then get confused when steemmonsters.club tells them they need a monster and a summoner, because to that player, they have all summoners and a lot of monsters - from their starter pack.
I was just suggesting that, if you can't have steemmonsters.club 'see' the cards from the starter, a different explanation for the error might be less confusing/frustrating for someone who got a free starter pack (many new players)... I will also bring it up with steemmonsters - they are the ones handing out those starter packs, they might need to make these ghost cards more known and understood, because they seem just like regular cards until an issue like this, or trying to combine, comes up.

Thanks for the hard work you do on steemmonsters.club -- I have been promoting it to new players and one of them ran into this issue, so I was just bringing you some feedback. Sorry.