Choose the kind of shop together
Your imaginary shop could sell clouds, songs or stories. You do not need real coins, small goods or special toys. One person describes the shop while the other chooses a customer role. Listen to unexpected rules your child invents; the activity need not become a lesson in performing real shopping correctly. Do not insist on changing roles if that interrupts an enjoyable shared idea.
Expand play with an invitation
Ask an open invitation such as what is available today or how you might carry a story home. If no answer comes, add a brief idea of your own and wait. There is no required sequence or length. Another day you can open a different shop or repeat the same idea without preparing new materials. Stop when either person wants a change.
Your next little step
Choose one idea that suits your family and try it at your own pace. Every family has different needs.
An example in practice
At a song shop, a customer might ask for something about rain. The shopkeeper can answer with a short hum. You do not need a receipt, a physical product or a finished song for the exchange to be complete.