John wrote:
Consider this scenario; Using FAA (USA) regulations.

A passenger wins a raffle prize or makes a donation to a charity, school
fund-raiser etc to win something. The winning item is an airplane
ride. The airplane ride is flown by a private pilot, who pays the
expense for the plane (rental, fuel, or time in her own plane). The
plane only lands at the same airport as it departs. In other words, the
passenger paid money, with the expectation of an airplane ride, although
the money isn't spent on the plane or pilot. Is this legal?

No, unless the flight complies with FAR 61.113(d).

Change the scenario to the pilot has a commercial rating. Does this
change the answer to the question?

It's not legal unless it complies with either 61.113(d) or the
following list: 135.249, 135.251, 135.253, 135.255, and 135.353 (per
135(1)(a)(5)).

Finally, if the airplane ride is to a destination at another airport and
then returning (after a few hours, overnight, weekend etc.) How does
this change the answers?

It's not legal unless it complies with either 61.113(d) or the entirety
of Part 119 and any applicable parts of parts 121, 125, or 135.