The so-called “sharing economy”, meaning peer-to-peer based sharing of resources, is growing at an ever increasing pace. Interestingly, the business models within the sharing economy are everything but homogeneous, covering exchange mechanisms that range from classical market exchanges involving negotiated prices to exchanges that do not rely on monetary payments. Past research has neglected the question whether different exchange mechanisms in the sharing economy may lead to varying outcomes. Based on social exchange and relational models theory, we propose that the success of market-pricing business models in the sharing economy in terms of motivating users to participate depends on whether the exchange relationship is perceived as a social or economic exchange. Further, we propose that market exchanges in the sharing economy may cause a crowding-out of prosocial behaviors of sharing. We test our hypothesized framework in two experimental studies (N1=440; N2=60). Results of these studies support the developed theorizing and have important implications for the design of sharing economy business models as well as their potential societal consequences.