In addition to the many different forms of poker, there are also some betting variations between the games and even within the same type of poker. These are called "No Limit", "Pot Limit" and "Fixed Limit". For example none of these types is uncommon for maybe the most popular form of poker "Texas Hold'em". Even though it's usually played as No Limit all these forms are acknowledged within the poker community.
On the table above the blinds are $1-$2 FL Texas hold'em. "assitoni" is under the gun and first to act, he can raise to $4 call, the big blind or fold. The following players can re-raise this in increments of $2 per raise until the maximum of $8. When the bet reaches $8, players are only permitted to either call or fold since you're only allowed three raises pre flop in fixed limit games.
The four times the amount of the big blind cap aplies to all fixed limit forms of poker. When the pre flop action is closed the dealer burns one card and places the flop on the board.
In this spot it's "komornik" who acts first and this players options is to raise the fixed amount of $2 or check. Just like the preflop the bets cannot surpass $8 and the remainder of the players can only call or fold once the bet reaches this amount.
It's when we get to the turn and river things changes a bit. Instead of the fixed raise amount of $2 it doubles to $4. This is the reason why a limit game with $1-$2 as blinds often is called $2-$4 since the earlier betting rounds there is a $2 dollar limit and the later rounds $4. There is however still a four raise cap on both on the turn and the river, in a limit game with blinds at $1-$2 dollar the turn and river cap will therefore be $16. No matter how many betting rounds there is always double the amount increase on the third betting round, in stud for example there is 5 rounds of betting with the two first being the low amount and the latter three double the amount of the big blind.
In pot limit there is just like in the fixed limit games a limit on the bet amount. In this case however there are some more wiggle room as you can raise anywhere between the amount that is already in the pot with the minimum being the amount of the big blind.
In this hand the blinds are $1-$2 which means that if a player opts for the raise it will have to be in the $4-$7 range. "YYYeaHHH" raises to the pot limit cap in this spot, since the small blind bet is $1 plus the big blind bet of $2 and your own $2 which would be the call if it were'nt for the raise. This adds up to $5 in the pot plus the $2 dollar which were the current higest bet equals $7.
This hand shows the betting action on the turn where "dogtal" raise thw pot limit which is $48 which and "El z0rz" re-raise the pot limit. Here is the calculation on this particular hand, $48 from earlier action in the pot plus dogtal's $48 with El z0rz's call before the raise counts equals $144 plus the amount from earlier betting rounds $48 makes the pot limit cap $192. The thing to remember when playing a home game for example where a computer don't calculate the cap unlike online games, is to count the amount the player would have to call and add that to the pot before calculating what the max raise is.
The name pretty much tells the story, in no limit games there is no max raise other then the size of your stack and the minimum raise which is the amount of the big blind or the amount of the last raise the same betting round.
In the hand above "pardama" raised $15, "Sebbe2506" may fold, call, or raise anywhere between $30-$393.26 which is what the player have left on the table. However since pardama has a lot less in his stack he would if his potential all in gets called take back the amount which is the difference between the two stacks, since the player can't win money that the other player doesn't have and vice versa. You can not add more money to your stack during a hand as they are doing in movies either, thus you can only wager the amount of cash you had in front of you when the hand started, no more no less.
Which variation you choose is a matter of preference, if you like the adrenaline you get when you run a big bluff you should stay away from the fixed limit. Fixed limit is however a smoother ride where putting your opponents on certain ranges in specifik spots in order to get value from marginal hands is a vital part of the game. Choose wisely.
Good luck at the tables!