A small business considering a purchase order system usually does not need a system so much as three habits, and the habits are what make any later software useful. Controlled numbering, one approval before the order is sent, and somebody recording what actually arrived. Established first, they can run on a shared sheet; established never, no software will save them.
Controlled numbering
Unique, never reused, issued from one place. In a small business this is the rule most easily broken, usually when two people raise orders on the same afternoon or a spreadsheet is restored from an older copy. Reused numbers make two transactions indistinguishable forever, and there is no fixing it retrospectively.
One approval, before it is sent
Somebody other than the requester agrees before the supplier is told. In a very small business that is often the owner, and it takes seconds. The value is not distrust; it is that the commitment becomes deliberate, and the person who carries the cash flow consequence has seen it before it exists.
A record of what arrived
Whoever takes the delivery notes what came, against which order, on what date. This is the step small businesses skip and the step that everything downstream needs. Without it, an invoice cannot be checked against reality, and the alternative is remembering, which works until the month somebody is on holiday.
Questions people ask about small business purchase order system
Can we run this on a spreadsheet?
Yes, provided numbering is controlled and only one person issues numbers. It stops working when several people raise orders simultaneously.
When should we buy software?
When somebody starts keeping a second spreadsheet to track what is still outstanding. That is the system trying to exist.
Do small suppliers accept purchase orders?
Almost always, and many prefer it because the reference speeds up their own payment. It rarely creates friction.