Bingo is one of my favorite activities on the ship!
They play 4 games per session. The cash prizes for the first three games are a not a set prize amount, rather a % of their take. The don't announce the amount until there is a winner. As each session is generally bigger than the last, the prizes get bigger as the cruise goes on. I believe for the first session on my recent Fantasy cruise the prizes were in the 150$ range, and by the end of the cruise, they were in the 3-400$ range. For the final game in each session, there is usually a jackpot prize in the thousands if you win in a certain number called or less (which hardly ever happens), otherwise there was a consolation prize, which was still the biggest for the session. At the end of the cruise the final jackpot must go, so if no one won it earlier in the cruise it easily gets hugs - usually around 8-10k!
It is true that the majority of wins come from the electronic cards, simply due to statistics. For most people playing the paper cards, they are playing 6 or 12 cards. The lowest package of electronic cards usually includes 24 cards, so that's 2-4x more chances to win. Many people buy the higher packages of electronic cards, which are 48 cards, so 4-8x more chances. Any card can win though! But simply since there are just so many more electronic cards out there a win on the paper cards is a lot more uncommon.
Hope this helps!
Aby