I hope it goes without saying but you shouldn't pay the outrageous amount charged for "Let There Be Range". It's a terribly written book, albeit with some useful content if you can suffer through it. So it might be worth $20 (but even then it's very unprofessional). As with any book, you could always say if something in there wins you one big pot, then is the book worth that much? But I'm simply comparing market values of these things.
Oh wait, I spoke too soon! If you act now, it's on sale!
https://www.dailyvariance.com/shop/p...here-be-range/