Well, statisticians can be thought of as kinda-mathematicians and George Pólya has remarked that
Mathematics is the cheapest science. Unlike physics or chemistry, it does not require any expensive equipment. All one needs for mathematics is a pencil and paper
Otherwise, e.g. pharma research and biochem in general can get pretty expensive.
In maths, you also need a waste-paper basket. Pólya must have been thinking of philosophy.
Many of the biggest historical success stories in philanthropy have come in the form of funding for academic research. This suggests that the topic of how to purchase such research well should be of interest to effective altruists. Less Wrong survey results indicate that a nontrivial fraction of LW has firsthand experience with the academic research environment. Inspired by the recent Elon Musk donation announcement, this is a thread for discussion of effectively using money to enable important, useful research. Feel free to brainstorm your own questions and ideas before reading what's written in the thread.