Consumers in many countries like the Kingdom of Saudi Arabia (KSA) are increasingly turning to social media platforms like Instagram and WhatsApp to buy and sell products and services. Commercial activities within these platforms are increasing in popularity because of important qualities they provide, such as convenience of use, social aspects, and the variety of the types of products available. Using social media in this way has become popular, even though social platforms lack support for conducting e-commerce. In our study, we aim to understand this new trend, to investigate the needs of social media consumers within KSA, and to investigate how social platforms can be better designed to meet those needs. Using data collected through interviews with 26 social media users, we discuss and propose design directions and trust mechanisms for supporting commercial activity within social media platforms with the aim of improving user experience and increasing user acceptance.