Use the buyer's account to test the daily inventory of the product. A simple calculation of the daily inventory on different dates can determine the sales of the product over a period of time. This method can relatively accurately determine the value, but it is too time-consuming, and some products will have purchase quantity limits, so calculations cannot be performed using this method for a long time.

3. Valuation by the number of reviews. The review rate on the Amazon platform may be relatively low. Some products may only get single-digit reviews after selling hundreds of copies, and the reference value of the number of reviews left too long ago is also low. This requires screening the reviews, retaining the reviews for the past six months or a year according to demand, and then calculating. The percentage of calculation is also very important and requires consideration from many aspects. The disadvantage of the third method is that it is difficult to calculate and the numerical accuracy is unstable.