[gmiller123456]

I certainly would not consider Musk a reliable source.

[Isinlor]

SpaceX is contracted to deliver people to the Moon surface for 2.8 billion dollars total (development + actual mission).

To do it they need around 6 launches for refueling in orbit.

The very upper limit on a single Starship launch is 0.5 billion (2.8/6).

[zardo]

The upper limit, with the assumption they don't lose money on the contract.