It can be done in InfoPath with Out of box solutions. I will try to elaborate the steps in details, please let me know if you have any question.
I made a simple demo in my end, the list name is called Product list. And in the form I will try to get needed information of the corresponding Ori Price and Exchange Rate.
Product list:
My form:
In my demo, I will try to use the title field to check the product list and get information.
- Create a data connection to get information. Remember to check on the required fields.
- Create a button for clicking
- Add rules for setting the field values.
Here is what we get: