Free shipping has become a key competitive strategy in e-commerce platforms, widely used to reduce cart abandonment and increase purchase conversion. However, evidence across studies shows that free shipping does not operate as a standalone determinant of consumer behavior as its effects depend heavily on complementary promotional mechanisms such as flash sales, discount depth, cashback, paylater, social proof, and interface cues. This critical review synthesizes evidence from experimental, survey, and qualitative research examining free shipping, free returns and platform promotional ecosystems. Findings indicate that free shipping tends to strengthen purchase decisions and purchase intention but demonstrates mixed influence on impulse buying, often being weaker than flash sales and cashback. Scenario-based evidence further suggests that monetary return fees may harm consumer–retailer relational outcomes by increasing brand switching intention through perceived brand transgression severity. The review highlights methodological limitations including overreliance on cross-sectional student samples, weak causal inference, and limited investigation of interaction effects. Recommendations are proposed for e-commerce retailers and platforms to implement targeted free shipping, transparent return policies, and ethical promotional design. Implications are discussed for theory-building, managerial strategy, consumer protection, and future research.
Joshi et al. (Thu,) studied this question.