noun
admission fee; enrollment fee; joining fee
A fee paid when joining an organization, club, or insurance scheme. Often a one-time payment separate from regular dues.
このクラブに入るには、加入金が必要です。
An admission fee is required to join this club.
保険の加入金は初回のみ支払います。
The enrollment fee for the insurance is paid only at the start.
入会金 is a near-synonym also meaning 'admission fee', often used interchangeably with 加入金.
Compound of 加入 (かにゅう, 'joining') and 金 (きん, 'money').