I find the Bingo to be TOO expensive with winnings that just make it seem not worth it. (i.e. you are not likely to win, and if you do, it's usually about as much as the cards cost you to begin with). The only except would be going for the jackpot if it has not been won by the last day of the cruise.
While I don't remember exact dollar amounts, I seem to recall that it cost about $30 for my wife and I to get a "standard" set of cards (3 cards per round with 5 rounds). It seemed like the winner of the first couple of rounds would get $30 to $50 (basically enough to make your money back for playing). Once the winnings got higher for later rounds, the game was such that usually multiple people won and the winnings had to be split (and it seemed that each persons share was something on the order of $30 to $50). Out of about three sessions (or about 15 rounds), I think there was only about two or three times were someone won more than $100.
Of course I never won (but like I said, you go into Bingo knowing you are not likely to win). I just found $30 to be too expensive to play some games of Bingo where you know you are going to lose, and if you win, your only likely to get back about what you paid for the cards to begin with.
I much perfered the way they used to play bingo at my parents country club. At the start of the evening, cards were $1 each and good for 10 rounds. They would take a break after 5 rounds, and additional cards could be purchased for $0.50. Pots started at about $10-$15, and quickly raised to $20 -$25. I think the last round of the evening was something like $50, but could be as high as $200.
Dad would buy us one card each at the start, and two more at the half. So for a family of 4, he was spending $8 for the entire night (10 rounds of bingo last about 2 hours). If we won just one round, we at least made our money back. But even if we didn't win anything, we still had 2 hours of fun for the whole family for less than $10. On
DCL, an equivilent amount of fun would cost about $120 ($30 for 2 for 5 rounds, so for a family of 4, that's $60, and you have to do it twice to get 10 rounds).
[EDIT]
In case things have changed, I should mention that when we last played Bingo on DCL, it was the year that they started offering Bingo. From what I've read here, it sounds like some changes have been made. As an example, when we played, children were NOT allowed to participate. They could be in the room, but Disney was so sturn about not allowing children to "gamble" that they would disqualify any cards handled by children.
So perhaps some changes have been made and my observations are no longer accurate. If I'm wrong, could someone let us know what a typical bingo session is like?