Purpose -Although word-of-mouth has been demonstrated to significantly affect sales, its impact on different types of products over time remains unknown. To fill this gap, this study examines the influence of product prices and brand on the relationship between word-of-mouth (WOM) and sales over time through a case study on four types of smartphones (high/low prices for strong/weak brands). Design/methodology/approach - Weekly sales data and online WOM of these smartphones were collected from the major Chinese shopping website Tmall.com for six months. This investigation is conducted within the frameworks of signaling theory, perceived risk theory, and uncertainty reduction theory. Findings - Results show that the influence of word-of-mouth on the four types of product sales vary across different sales periods. With the rapid growth in the Asia-Pacific market and the number of global smartphone users, the present study provides empirical evidence for the impact of WOM on smartphone sales in the Chinese market. Research limitations/implications - This study only inspects four models of smartphones with different brands and prices in the Chinese market. Future studies may include smartphones in different price segments for a more comprehensive analysis. Practical implications/Social implications - The results provide important references for smartphone companies to develop marketing strategies in different sales periods and offers a conceptual framework for future research. Originality/value -This paper provides valuable insight into the temporal dynamics and effects of WOM on smartphone sales and offers a foundation for future product branding research.