Like every other product, the price of a microscope depends on several factors. How good is the brand, the application of the microscope, the instrument quality, accuracy, etc. have a direct impact on the pricing.
In general, a microscope price can vary from around $150 to $2000+. You can buy a pocket microscope spending less than $100 too.
The best way to get the real picture is to read any microscope review/comparison article or to compare the price of different brands and models from their websites or an online platform like Amazon.