which component should i put the better cable on?

I have two different power cords one costing $250.00 the other $1000.00. My question is which one should i use on which component? Should i put the better powercord on the amp because it uses more power because it is a amplifier or should i put the better powercord on my pre-amp, and if so on the pre-amp why!? I would appreciate any input please! Thanks for looking!
Phil (audiophill)