They had spa bingo on our cruise and it worked like this. When you bought your game cards you also got a paper ticket (1 for the play-3-games-at-once-pack and 2 for the play-6-games-at-once-pack. They individual bingo games were still for cash prizes but in between each game they would pull a ticket out of a bowl. If you had the matching number you would win the prize for that round.
I would guess jewelry bingo is similar.