The buy-in is the amount of money required by player to sit down in a particular poker game. All real money games at have a minimum buy-in required before a player may join a table. Blitzpoker
Minimum and maximum buy-ins
The minimum buy-in requirement for Limit Poker is 10 times equal Big Blind. There is no maximum buy-in.
Example: In a 1/2 limit game, the big blind value is 1, so the minimum buy-in is equivalent to 1x10, or 10.
Pot and No-Limit poker
Pot-Limit and No-Limit games have a minimum and maximum buy-in.
The minimum is usually 20 times the small blind and the maximum is usually 100 times the big blind.
In a 1/2 No Limit or Pot Limit game, the small blind is 1 and the big blind is 2, the minimum buy-in would be 20 and the maximum buy-in would be 200.
All games and tournaments comply with the following table stakes protocols:
No chips can be added to a player's stack during a hand.
Players can add to their stack between hands only. While some tournaments offer re-buys and add-ons, these can only be made after a hand is over and before the next hand starts. However, players can add chips or re-buy and add-on during the hand if they are not involved in that hand.
Players can not take out chips from the table.
Player cannot take out any chips from the table during play until he leaves the game. This rule applies regardless of how many chips player has brought to the table. The table stakes protocols are designed to protect the game.
Otherwise, if player is allowed to put a few chips into his pocket every time he or she is ahead, then the number of chips available for play will be reduced and the action at the table will suffer.