We know more about some ordinary people than others in Mali around the time of Mansa Musa.

Mande-speaking societies throughout West Africa have a distinctive social structure with people who have important technological skills associated with particular forms of craft production. Known as nyamakala, these people (blacksmiths, potters, weavers, leatherworkers, bards) lived in separate communities and intermarried. Their socioeconomic lives tended to be tied at least somewhat to the imperial courts and military nobility of large states in the region like Mali, Ghana and Songhay, particularly smiths and bards. When those states were prosperous and well-administered, there's good reason to think that carried over into the lives of the nyamakala. But just to focus on Mali, there was fairly regular dynastic instability in between the era of Sundiata and the rise of Sonni Ali of Songhai, and that likely affected nyamakala communities either simply by decreasing demand for their goods or by making transport and security of their goods more precarious.

Nyamakala were not a very large proportion of what we might think of as ordinary people within the approximate boundaries of these Sahelian empires, however. Far more numerous were settled farmers, fishers on the Niger and Lake Chad, and pastoralist herders of various kinds, many of them not Mande-speakers. It's a lot harder to say specific things about their relative prosperity or comfort over time, except to say that Sahelian societies in Senegambia and the Niger bend seem to have had long periods of stable food security except during cycles of drought.

Roderick McIntosh writes about the Niger city Jenne-Jeno in Volume 3 of the Cambridge World History, and it's a good guide to what ordinary life was like within Mali. He points out that Jenne-Jeno was hard for Western archaeologists to understand when they first realized the scale of the city's ruins because it was neither a cosmopolitan city shaped by the trans-Saharan trade and contact with the Islamic world like Timbuktu or Gao, nor was it an imperial capital shaped by a royal court. McIntosh argues for an "emergent urbanism" between 400 CE and 1400 CE in the middle Niger region--that large urban settlements formed and became increasingly elaborated around trade between farmers, fishers, herders and nyamakala. He sees Jenne-Jeno as a place relatively lacking in hierarchy that contributed a great deal to a sense of greater security and peace throughout the region and that produces a progressively greater feeling of an ability to manage the long-term shifts in the region's climate.

Roderick and Susan McIntosh have suggested that the slow decline and eventual abandonment of Jenne-Jeno after 1200 CE may have had something to do with the Islamicization of imperial courts in the region and shifts in the trans-Saharan trade, with pointedly non-Islamic settlements like Jenne-Jeno suffering as a result. Whether or not that's the case, I think you could say that somewhere around 1100 CE or so--about 200 years before Mansa Musa's reign--the material and everyday life of ordinary people in the middle Niger had become more secure and prosperous. Much of that probably remained the same even after the decline of any given urban settlement (or the rise of others) but it's possible that competition and rivalry between major imperial cores and tensions between Islamic and non-Islamic communities may have made life more precarious or uncertain after 1350, and that the ebbing of the trans-Saharan trade after 1650 made that trend even worse.