Final answer:
The best way to spend the money would be to invest in instruments and observing programs targeting the search for brown dwarfs, such as a high-resolution spectrograph and an observing program at a dark sky site.
Step-by-step explanation:
To search for more brown dwarfs, it would be best to invest the money in instruments and observing programs specifically designed for this purpose. A recommended instrument would be a high-resolution spectrograph, such as the Keck Observatory's HIRES, which can detect the characteristic signatures of brown dwarfs. Additionally, allocating funds for an observing program at a dark sky site, like the Cerro Tololo Inter-American Observatory, would provide optimal conditions for observing these objects.