Food is priced against two timers: the one printed on the pack, and the one that starts when the parcel leaves.
What moves the number
The date, and which kind — a best-before is about quality, a use-by about safety.
Whether it is sealed.
Scarcity — something that cannot be bought outside one region carries real value.
Batch size, and whether it is a one-off.
How far it can travel safely, which decides how many buyers there are.
Why two of the same differ
One listing shows the date, the allergens and the seal on camera. The other shows a photograph of the packet. Describing food honestly.
How to find out rather than guess
Compare completed sales with similar dates and similar delivery terms. A collection-only perishable sells into a local room; a shelf-stable packaged good sells nationally. Those are different prices for the same food.
Before any of this
Two questions come first, and they are not about price: do you hold what the law requires for what you are selling, and will a courier carry it. The selling guide sets both out, and the policy is explicit that the licence question is yours rather than ours.
What is usually not worth posting
Anything that must stay cold, anything close to its date, and anything heavy and cheap — where delivery costs more than the food.
Questions people ask
Can I sell past a best-before?
Only with the date stated plainly. A use-by date must never be passed.
Are hampers worth more than the parts?
Usually, presented well, with every date stated.
Is local-only a disadvantage?
It is a smaller room, and for most perishables the only honest one.
More: pricing food, packing it.