We experimentally study the common wisdom that money buys political influence. In the game, one special interest (i.e., a corporate firm) has the opportunity to influence redistributive tax policies in her favor by transferring money to two competing candidates. The success of the investment depends on whether or not the candidates are willing and able to collude on low-tax policies that do not harm their relative chances in the elections. In the experiment, successful political influence never materializes when the firm and candidates interact just once. By contrast, it yields substantially lower redistribution in about 40% of societies with finitely repeated encounters. However, investments are not always profitable, and profit sharing between the firm and candidates depends on prominent equity norms. Our experimental results shed new light on the complex process of buying political influence in everyday politics and help explain why only relatively few firms do actually attempt to influence policymaking.