Braid can be used for free, however there fees for optional features:
Credit Card Contributions
Braid charges a 3% + 30¢ fee for Pool Link contributions made with a credit card. This fee is charged to the contributor so it does not come out of the contribution amount. There is no fee for contributions made with debit cards.
Braid charges a 1.75% fee for instant transfers from Braid to a bank account. There is no fee for standard bank transfers.