And there I was thinking I could just bung someone a crafty C note for a belly full of Avgas
It would have to be an awfully small plane! In my plane (TR182) a round trip PHX-LAS would be around $300-400 in direct operating costs. A smaller plane would be cheaper per hour but would take longer, so not much difference. And that assumes I'm essentially doing it out of the goodness of my heart or to build hours. If I want some compensation for my time and to recover some of the overhead costs of the aircraft, it would be double that.
That said, if you find someone who'll do it quietly for the cost of fuel, good luck to both of you. Just don't get caught, and don't tell a soul what you're up to.