Unlike an online casino, an online poker site never bets against the
players. Instead, it charges the players a fee to use the poker server.
There are two kinds of fees: rake collected from ring game pots and entry
fees charged in tournaments. Each poker site has its own “rake
schedule” that defines the amount of rake that is removed from each
ring game pot. These vary by site, but a typical rake schedule is 10% of
the pot in increments of $0.25 up to a maximum of $3. In a $1-$2 game
where the average pot is $12, the average rake would be around $1.25, or
about 12 cents per player per hand. In games with stakes of $5-$10 and
above, the pot is usually large enough that the maximum rake of $3 is
applied to every pot. Some sites don't charge any rake if everybody folds
before the flop (“no flop no drop”) and most sites reduce the
rake when games get short-handed.
Tournament entry fees are typically 10% for the lower-stakes events: $1
for a $10 buy-in (written as $10+$1), $2 for a $20 buy-in, and so on. The
$10 goes into the prize pool and the $1 goes to the house. The entry fee
for larger buy-in events is usually a smaller percentage, for example
$100+$9 or $300+$20.