Need recommendations for inexpensive power cord

I’ve never used after market power cords and am considering buying a couple.  I have some questions:

Considering the astronomical price power cords go for, is there any point getting one or two in a lower price range?
At what price point do power cords start to make a difference in your system?
I have two monoblock NuForce class D 160 watt amps.  Is this where they should go? 
Can someone recommend an inexpensive power cord that can make a difference?