It depends on the number of employees and locations. Very large companies (including the United States Government) make discount deals with manufacturers and wholesale suppliers of the necessary goods and then supply a catalog of the items represented by those deals to employees (now computer-based.) Some of the items are purchased in bulk and supplied from the company (buyer) storage. Other items are ordered and shipped direct from the supplier.
Smaller companies (as mine was) set up similar deals with wholesalers and retailers and do not store any bulk supplies. For example - we bought copy paper by the case (10 reams), whereas an advertising company down the street bought paper by the skid (12 cases.) We used purchasing cards tied to American Express and Visa and eliminated the soft costs of dealing with purchase orders, invoices. We kept a list of the suppliers with whom we had a deal and bought primarily from them. Occasionally, we needed something not carried by them and went to another supplier. The fact we used a purchasing card with a new supplier usually meant we could have items shipped the same day without a credit check or waiting to prepare a purchase order. The purchasing system system only applied to small ticket purchases (less than $100 without a manager's approval - a clerk could order packaging tape without involving a manager. Bigger ticket items up to $500 only needed approval from one manager which could be via phone, not waiting for a piece of paper routed for a signature.) One wholesaler we dealt with had a deal with UPS so that if we ordered before 10:00 am, we could get delivery the same day. This wholesaler also handled shop items like hand tools, cleaning fluids, lubricants, etc.
Sometimes we paid a little more than if we shopped really hard, but the savings in soft costs more than made up for it. Reconciling purchases at the end of each month was a snap - the suppliers provided printouts of the month's purchases and delivery dates along with prices paid - we compared those against the purchase card printouts. Our pricing was usually based on assuming a yearly purchase total of ALL goods rather than on a quantity in a single shipment, thus our one case purchase of paper was close to the case price paid by our neighbor who bought 12 cases in one delivery and only about half the retail price for one case at an office supply store. If there was no rush, we usually got free delivery within two days since the supplier's vehicles were in our commercial/industrial district every day. We kept tags on shelves where consumables were stored to reorder when stock (paper, printer ink, shipping cartons, label stock, etc.) ran low. We had our company logo printed on our shipping cartons, but our supplier only needed two days notice to print and deliver as few as 100 cartons, even in custom sizes. In 1995, we calculated we were saving $2,000 year (rent, maintenance, carrying costs) by not storing two months supply of cartons on our premises. Yep. We were poster kids for JIT. We had similar deals for raw materials like steel bars and nonferrous stock like copper, brass, aluminum, titanium. We paid for everything with the purchasing cards. I only wish I could have convinced some of OUR customers to pay us that way - I would have willingly paid the card fees to avoid invoicing and dunning late payers.
Added in edit:
It occurs to me to add that many companies now use a purchase card system for purchase of MRO (Maintenance, Repair, Operations) items.
