(1) A commercial-logo [or two ...or three...] on the side of a spacecraft, here.
(2) Some toy-company interested, in a deal, there.
(3) Maybe a rock-group wants to shoot a video with
a static rocket-motor firing away in the background [they could
pay for the propellant].
(4) Maybe a shapely model interested in spaceflight wants to go up on a private "space-tourism" mission, bringing welcome publicity and
funding [It can happen!].
(5) Perhaps an electronic package (with handycam) aboard a private spacecraft can serve as a temporary internet website during it's premier sub-orbital "testflight". To log-on, space-fans have to have their
credit-cards handy.

Look! None of the above suggestions ALONE can fund an entire
private space-project....But little things, if there's enough of them,
do add up!...
And even a major sponsor/patron may refuse to pay for COST OVER-RUNS.
Cost over-runs for private space-projects?...NASA isn't the only one
vulnerable to such nasty circumstances.

Thus the little things I've suggested to cover those costs.
Some suggestions will work; some won't...They just got have to be suggested...however ludicrous, or [conversely] however viable.

cheers.

Jacob