You would have to pay a lot more than buying time on existing instruments. You would have to pay for the construction of new and very expensive instruments
You could pay to have copies of the Gaia spacecraft built and sent into orbit around the giant planets in our solar system and/or at their L4 and L5 positions. Thus two or more such observatories could study the same star at the same time with a baseline between them tens of times greater than the baseline resulting from the orbit of the Earth around the Sun. Thus the parallaxes and distances should be tens of times as precise.
And if you pay for the development of more precise instruments than Gaia has, you can increase the accuracy and precision of the parallaxes and distances even more.
And you could pay to have several such observatories sent out of the solar system in various directions so that they will eventually be separated by even greater distances than the outer planets are, thus making their parallax and distance measurements even more accurate.