Any charging of the donor, by doctor, hospital, or third party, violates Federal law. Any bills a donor gets come by mistake. It doesn't impair you, or shorten your life, to share it with others, as you were born with two kidneys, and can do perfectly well with one. It isn't risky. People who'd be at risk from the surgery aren't accepted as donors.
Live donors are healthy people.
Donation surgery is safe for the donor. And you're back on your feet pretty quickly.