[pzhon]

Someone will win. (There may be ties.) If you have n cards out of m, your expected share of the prize pool is n/m. If you buy more cards, you can increase the probability of winning, but you can't expect to win 100% of the prize pool. There will always be a chance someone else will win.

Typically, 50-90% of the entry fees go into a prize pool split among the winners. The rake is huge, just as for keno. It is a way that people can gamble and lose socially.

BINGO can be +EV in hypothetical situations. In live games, your opponents may play badly, particularly if they are playing many cards at once. However, if this is what they do for fun, expect those old ladies to be faster and more accurate than you. Online, the play is handled automatically, but you can get some bonuses. In both settings, there may be progressive jackpots on coveralls: If you cover your entire card within 50 calls (66C26/90C50 = 1 in 36.2 million), you may win the jackpot theoretically funded by past players. However, these jackpots always seemed tiny compared with the odds against winning them. <font color="white">Technically, you don't win the jackpot if someone else wins it first, but that is negligible.</font>

In my brief look at online bingo, I found the rake to be so bad that it was not possible to make a decent amount from the bonuses.