We're using Store 2.3.1 for a company based outside the US, but who sells to the US market. They've asked if we can reduce the price of the product by 18.7% if the customer is from the US. Is this possible?
There isn't really a way to apply a discount based upon a users location but you should be able to do this fairly easily via a tax setting of 18.7% other then the US. Other then that you would have the option to either create a discount then pragmatically apply it after a user entered their shipping/billing details or the more robust option of creating an extension to apply the discount based upon a users location.