One hack for buying cheaper flights can involve logging in through an alternate country portal to take advantage of lower fares in a certain currency.
However, be forewarned: As this rule applies to travel to and from the US, some international airlines’ websites will not have these policies built into their sites for customers in other countries, creating more of a process to get the cancelation without penalty (you’re still covered under the rule but it might take more time/hassle to get the refund).
So, if a carrier has country-specific reservation portals and you think you might want to utilize the 24-hour rule, it might be worth your time to make your booking on the US site.