That depends. In most cases, the Cheerful platform will utilize the ACH payment mechanism available at your issuing bank. In this case, only ACH fees are taken at a 0.8%, which equates to about 4 cents on each $5 transaction.
There is a rare case where your bank will not allow a withdrawal using the ACH payment mechanism and will require you to enter your credit card details to make the payments. If this occurs, there will be a 2.2% + .30 cents fee on each $5 transaction. You can cover this fee to ensure your cause receives 100% of your donations.