When joining a poker tournament, a percentage of the buy-in amount is taken by the house as a fee. The fee amount is different for each type of tournament.
For example, Twister tournaments feature a maximum of 7% fee on each buy-in. Other tournaments display the fee amount in the client; this varies on the type of tournament up to a maximum of 10%.
You can find more information on fees on our House Rules page, in the ‘Rake and Fees’ section at the bottom of the page.