We're often asked how to report on donations with transaction fees also accounted for on the same report. This isn't possible with Salsa because we do not actually charge/store the fees. Those are entirely handled by your merchant gateway which processed the transaction. More on merchant gateways (including some fee information, to the best of our knowledge):
Salsa used to operate closely with a specific merchant gateway, Democracy Engine, and previously used to attempt reporting on their fees. Their fees, however, are completely controlled by them, so we no longer attempt to report on them (if a fee changed, and we weren't made aware, then we would be outputting bad reports...not good).
The absolute best thing to do is to reach out to your merchant gateway to verify fees, then export donation reports from Salsa, and then apply the fees as necessary in some outside spreadsheet software using a calculation formula.