From their webpage...
"Additionally, several people have actually offered to pay me for Hermes, or
give me donations for it. I do not want to sell Hermes. I want to keep it
free. But I wouldn't mind getting a little money from people if they wanted
to donate some to the cause. Maybe it'll help pay for a bigger download
pipe. To this end, I've opened a PayPal account, and can accept donations
through that. Click the button if you are so inclined. Remember, there is no
obligation, and Hermes is FREE."