In a poker tournament entry is through a 'buy-in' which means they all enter for the same amount of money. The poker room charges an entry fee that each player must pay for entering the poker tournament. Consider this- if the tournament buy-in is $100 and the house charges a $10 entry fee, each player must pay $110 to enter the tournament. If 150 players enter, the prize pool will equal the number of players times the buy-in, in present case 150 X $100 = $15,000 prize pool. The exact structure of the pay outs is established by that tournament however, generally there will be a prize for about the top ten players with each prize being a set percentage of the prize pool. As an example, the first ranked player might receive 30 percent of the pool, second place 20 percent, third place 15 percent, etc.
In tournaments, every player begins with the same number of chips and, over time, the stakes are raised periodically, perhaps every 15 to 60 minutes. The stakes, number of chips, and the time periods between advances in stakes defines whether the tournament is slow or fast. Expert players choose slow tournaments because they begin with lower stakes, more chips, and longer time periods. This provides the better player with the maximum chance of outfoxing the other players before the stakes are raised to such a level that they must merely gamble too much.
If there are a large number of players, such as the 150 and above, the tournament play frequently begin with tables of ten players each. As players use up all their chips, they get removed from the tournament unless they buy-in again, which some tournaments allow during a specific time period. Once losing players are eliminated, tables are rearranged so that the number of players are each table remains as close to equal as possible. Finally, the tournament play boils down to only one table and the winner is one who wins all the chips.