Why is Pahom confident that he can get a better deal than he imagined?

Pahom has been so blinded by greed, so obsessed with the acquisition of land, that it's seriously clouded his judgement. When he encounters the Bashkirs, he sees a great opportunity to add to his already extensive landholdings. Pahom finds the Bashkirs to be the ideal people from whom to purchase land. They come across as incredibly naive; they don't seem to realize the potential value of the land beneath their feet. Their naivety—as Pahom sees it—is expressed in what the grasping Russian peasant sees as the unbeatable offer they make him: the Bashkirs will sell Pahom as much land as he can traverse by foot in a single day.
Pahom seriously underestimates the Bashkirs, and he pays for this with his life. As well as finding them naive, there's a suggestion that Pahom looks down on the Bashkirs as racially inferior. The Bashkirs were one of the numerous subject peoples of the Russian Empire, and as such they were regularly on the receiving end of Russian chauvinism. Despite coming from a humble peasant background, there's every reason to believe that Pahom regards himself as superior to the Bashkirs on account of his membership of the empire's dominant nationality.