by nerman8r
An variant that seems obvious to me is to discard one card from the selection when no one's buying cards. It would work like this:The three available cards are placed in a row next to the deck. If the card closest to the deck is purchased, simply replace it. If another card is purchased, move the card(s) closer to the deck down a spot, and place the new card next to the deck.
Whenever a full round passes without anyone buying a card, discard the card furthest from the deck, move the other cards down a spot, and place a new card next to the deck.
Hope that makes sense. It's late and I don't think my writing skills are up to my usual standard.