tl;dr – Some easy savings on your next road trip in a rental.
Amex recently refreshed some of its merchant offers, and there’s a new one with Budget Rental Car, where you can save $40 on your purchase of $200 or more:

Note: The terms of this offer specify it’s valid for US rentals.

As this offer is triggered by both online and in-store locations at the car rental facility, there may be an opportunity to split the cost of a rental of $400 or more at checkout/return onto two Amex cards (each of which is targeted for this offer) to double your savings. (You can also easily check other merchant offers on other cards from other banks to see if there’s a similar opportunity to save money.

Like any Amex offer, you’ll want to add the offer to your card (in your Amex dashboard) before paying for your rental.