Does it cost anything to enter?

Registration on this site does not ask you for a payment or a wallet — there is no checkout in the entry flow. If a particular event ever carries an entry requirement, it will be stated on that tournament's own page and in its announcement.

Treat any message asking you to pay someone, send tokens, or share account details to “secure a slot” as a scam, whoever it appears to come from. Entry happens on the tournament's page and nowhere else.