Using data from market survey in Africa, we show that, according to the degree of processing of the cereal, market prices reveal (i) consumer preferences concerning quality attributes of the cereal, (ii) the characteristics of the suppliers (place of sales) and (iii) the abilities of the consumers to assess the quality attributes. We used a PLS (Partial least Square) procedure to estimate the role of each modality of the chosen attributes in the determination of the price.