RoughRomanMemes

Depends on the exact army/time period, but oftentimes, yes. 'Requisitioning' food from locals was also extremely common.

Both Greek militia hoplites and professional Macedonian phalangites are noted to have had to buy their own food. A 'good' general's contributions to logistics in this system was the organization of foraging parties to distribute food while on the march, but also the organization of military markets to enable the troops to buy their food when foraging parties were unavailable or insufficient. In Medieval Europe, buying supplies for levies was often up to each contingent's liege-lord and commander, and attitudes ranged there from 'attentive' to 'neglectful'. In the Crusades, it's noted that men would die for lack of food while others in the army had supplies; and that theft of food from the well-off by the poor was a major issue (one presumes to the well-off, rather than the poor).

By contrast, the Roman legions, even before they became a professional force, developed a system of guarded supply lines, with supply depots and distribution centers, and simply deducted the (meager, nominal) pay of the legionary militia for it.

Note that this doesn't preclude Roman soldiers buying food to supplement their rations, nor the Roman legions ravaging the land like a swarm of locusts - both occurred. In fact, considering that the Romans' logistical system was well-developed, ravaging land could be more thorough than under other, more ad-hoc systems. But purchase of additional foodstuffs was not strictly speaking necessary for the legionary, while it was one of the main sources of sustenance for many other cultures' soldiers.