A requester accesses a collection center system (4) and requests collection of expendables (S302). The collection center system (4) confirms actually collected expendables (S312) and gives a point to the user as the requester. For lump-sum collection using a predetermined container, a bonus point is also given. The point is also given for purchase. For the next purchase, the requester can receive an incentive in accordance with the point and enjoy a special service such as a discount.