The growth of sharing economy platforms is reshaping the boundaries between different market participants and leading to the development of innovative business models, raising numerous questions for both academics and practitioners. In this paper, we consider an online sharing economy system consisting of a powerful e-tailing platform and a budget-constrained small and medium-sized seller (SMS). As a reflection of the current practices adopted by Amazon and Tmall, the seller and platform engage through a consignment revenue-sharing contract, whereby for each successful sale, the platform takes a predetermined cut of the sales revenue. Due to factors such as information asymmetry and high degrees of operational risk, the SMS cannot usually access commercial banking loans, thus lacking working capital for further growth. To bridge this liquidity gap, an innovative financing scheme called platform-based financing has been launched by platforms to alleviate the financing issues that SMSs face. We establish a theoretical model to investigate the value of this innovative platform-based financing scheme and present several findings. First, we show that the optimal sales price can decrease when budget constraints exist. Second, we identify a threshold under which an SMS should accept a loan. Third, a platform should always provide financial aid to a seller who is short on funds, which always benefits the platform itself. Moreover, we show that both a seller and a platform will benefit from this innovative financing plan, improving the performance of the online sharing economy.