During the principate period, at least until the late 2nd century CE, new legionaries generally “bought” equipment from the army – they were given things from the legionary resource, and their cost was deducted from soldiers’ payments.
Sometimes legionnaires simply repurchased armaments from retiring soldiers or received the equipment as a gift.
With the passage of time of service and increasing financial possibilities, legionnaires more and more often retrofitted or replaced their equipment with better ones, already on their own.