In my experience cash and miles are super correlated, at least for domestic flights where if I search for some city pair and dates I actually want to travel rather than optimizing for deals I am almost certainly going to see around 1.3cpm, which becomes 1.5cpm after the Amex discount. International destinations seem to get priced by more arcane means and sometimes offer outsized value. And then sometimes domestic inventory gets dumped at anomalously low mileage. This page seems to have a better-than-random chance of highlighting those situations but its definition of "deal" is in general mysterious and for instance the things it's currently showing me clock in right at 1.3cpm as usual: https://www.delta.com/us/en/flight-d...es-award-deals

I also remember an old "skymiles flash sale" page (in the old website style) that I can't find anymore, so perhaps that has been deprecated.