Pay By Group charges a small fee in order to cover the costs of credit card processing. Fees only apply if the group completes.
The current fee for joining a Pay By Group can be found in our Fees section. If you're a group organizer, it costs you nothing to join your own group, and you'll pay no fee on the amount you collect to your bank account.
Clicking "Join In" on any Pay By Group will let you see the "Service Fee" section as shown below. If you've already joined the group, click "Edit Details" instead. If nothing appears there, there is no fee to claim a spot.