Nick Wright does a good job on the sticker shock with Mahomes. Costs $28M for Kirk Cousins and Jimmy G. That's the baseline for QB's in the league nowadays, so it's better to think of Mahomes at $40M in comparison to the $28M it would cost to have a typical QB in the league at this point...instead of comparing the $40M with Mahomes' rookie price at $4M.
https://www.youtube.com/watch?v=L_FgdhY2y_w