We love to play the bingo. If I recall correctly, the cost is $25 or $30 for a group of cards & yes they charge your seapass. We will be on Freedom in a few days so when we get back I'll tell you exactly how much the cost is.
On our cruise on the Inspiration we won $250 on a bingo game. It would have been $500 but someone else bingo'd at the same time, so we had to split it. Even though it wasn't a huge amount, we were very excited to have a little extra spending money for the rest of the cruise.
On the Voyager of The Seas- the last day at see they had BINGO...I thought it was $35 for the sheet of "cards"...my memory fades...anyway they played in the big auditorium and the place was packed. I believe it was 6 games and each game had a higher prize $$$. I would have sworn the last game was like a $1000...but then again maybe my mind has faded for good.
Yes, you can win cash. I saw a guy from England win $10,800 and watched them count out the money in cash. He only played the last game of the cruise. I can't imagine being so lucky. Although, my wife did win $280 cash on one cruise.