Is it possible to set dynamic pricing?

I will have a field that people will enter sizes for a drapery, and I want to add a cost depending on selection. Is it possible?

e.g., the customer is going to enter the following size in inches.

if the customer enters a value lower than 48 the price would be $237

if is between 48 and 60 price will be $254 

is it doable?

It's possible to conditionally inert values to fields and then pass this to the payment field if needed. 

This guide will help you conditionally inserting values: https://www.jotform.com/help/268-How-to-Insert-Text-or-Calculation-into-a-Field-Using-Conditional-Logic

These guides will help you capturing the value in a calculation widget and then passing this to the payment field:

https://www.jotform.com/help/259-How-to-Perform-Form-Calculation-Using-a-Widget

https://www.jotform.com/help/275-How-to-Pass-a-Calculation-to-a-Payment-Field

If you have questions, let us know.