Deuteronomy 2:6 - Joseph Benson’s Commentary on the Old and New Testaments

Buy meat of them for money For though the manna did yet rain upon them, they were not forbidden to buy other meats when they had opportunity, but only were forbidden greedily to hunger after them when they could not obtain them. Buy water For water in those parts was scarce, and therefore private persons did severally dig pits for their particular use.