How to call the pricing engine from outside of a Sales Order?

Summary:

We are currently attempting to build a custom screen for our client on which we will need to have the ability to calculate the "Your Price" value which is calculated on the Sales Order. We are looking for the ability to call/ping the pricing engine through an API or some other method from outside of the sales order screen to be able to calculate this value from our current price list and discount list setups. We will provide necessary inputs on the screen of customer, item, order type, etc. to be able to get to the calculated value.