Shops where people use to go daily or regularly should have a website. Where they can give what is available in their shop. And update that available info regularly. Customers can check whether it has their demanding item or not. If yes, then they can send the shop keeper their list. Shop keeper can make a packet of that list when the customer comes to their shop can hand it over and get the payment. If the shop doesn’t have their necessary things then they can ask for it, to the shop keeper through the website. Then shopkeeper may bring that thing (or may not, if not then will inform them) and make it in the available list. So, customer can go to the shop and buy their things.