The online casinos have many ways of rewarding its loyal players, and the "comp points" (comp from complimentary) is one of the biggest perks to the online gambler.

 Every time you wager at the online casinos, you accumulate comp points respective to your wager. You can then redeem those accumulated comp points for money to play at the casino. Please, note, that like any other bonus, the comp points also have a wagering requirements before cashing out.

 Here is a simple example of the comp points (also loyalty points) system:

 For every $10 you wager at the blackjack table, you are being awarded 100 comp points, and every 1000 comp points equal to $1. So if you wager $10,000 dollars, you will accumulate 100,000 comp points, and get $100 free. Keep in mind that "wager" means the money you bet, and not necessarily the money you loose, so it's very possible that you wager $10,000 with a single $100 deposit.

 Take a look at the online casino's comp points system. Some online casinos have levels of their loyalty programs, such as Silver, Gold, Platinum etc, which give you more comp points for your wager.