Can i give a discount on an ISP?

Is there any way to offer a discount to a specific group of people who use my Alexa app on an ISP?

as I know, there’s no control for changing price dynamically by developer and also it is not allowed to include price information in skill’s speech text. Only Amazon can do this(ex. discount for prime).

This is something you can do by creating multiple products. One at the normal price and another one with the discount price.