The type of customer who will visit your shop depends on the advertisement method used. Each type of customer has different preferences about a product, cheapskates want to buy products below their list price, and Big spenders are more interested in a product with the best performance and great build quality.
Every customer has a mood bar over his head, when he is checking out the product it shows his conviction to buy the product. In some cases, they need further assistance or you can just negotiate with the customer to sell product.
While negotiating with the customer, look into customer detail to see his type. It will help you to perfectly set attribute points while creating a sales pitch. While Tech-savvy customers will like you to talk more about the product's performance but it can backfire if the product's performance rating is bad. You can also offer customers an additional discount to close the deal.
If the product's build quality is poor then there are more chances that sooner or later customers will return to the shop to return the product it is up to the player to accept or reject the service request.
If the popular product is not available then sometimes customers will request to buy it. Again it is up to the player to accept or reject the request.
You can use marketing to attract a particular type of customer and increase their frequency of visits. Current shows types of customer you are attracting, while potential shows change in future after adjusting marketing budget with different options.