Is not only the price of the product you are selling, but also the price of the products that your competitor is selling. This factor influences customers' demands because if two identical products are at different prices, most people would purchase the one that is cheaper.
Use of credit
Refers to two things: either the credit terms of products or the credit terms for your credit cards. It influences customers' demand because people usually buy more with credits than with cash.
Disposable income
This is the income you would have after purchasing all the necessities such as water, and food. This influence people's behavior because if customers have more money to spend, they are more likely to purchase more products than people who have less money to spare.
willingness to spend
Refers to the maximum amount of money a customer is going to spend-on when purchasing a product. This influences customers' behavior because if the price of a product is over the willingness to spend of customers to which, the customers wouldn't purchase that product.