In our societies, any kinds of products or services must need to apply demand and supply economic theory to analyze whether the kind of product or service may be value to invent to sell or serve to their customers in consumer market, if the kind of product or service demand number is less, then it ought not to raise manufacturing number to avoid "low price " sale or if the kind of product demand number is more, then it ought raise manufacturing number to have enough number in order to raise " high price" sale to satisfy customers their needs to buy their products. However, whether your product or serive's demand number depends on supply number or your product or service's supply number depends on demand number in order to make ths sale price is reasonable high or low level and reasonable supply number valuation. In my this book, I shall indicate some actual product or service social suitation to explain whether it is right time to these kinds of product or service of their sale price ought increase or demand in market demand and supply environment in order to avoid customers number reduce. Readers can learn sale price strategy of these sale cases studies.