The aim of this research is to highlight the impact of the mediating effect of the perceived value on the influence of perceived quality of the purchase-site on the buying intention, Moreover; our goal is to study the moderating effect of accompaniment on the relationship between the perceived quality on perceived value web site. The data-gathering was carried out through an experimentation conducted an online-trading site for a laptop purchase. The findings reveal that the perceived quality partially influence the perceived value. The latter exerts a positive effect upon the buying intention. Accompaniment moderates the relationship between the perceived quality and the perceived value.