I need a Displayport/HDMI to VGA cable.

Can't do DP to VGA without an adapter, you should use an HDMI-VGA adapter right at the GPU if you are going to use one, but by the nature of this question i suspect that none of those will actually solve your problem.

What are you actually trying to do because an Amazon search could have easily found an answer, but likely not solved the true problem here....
 
Unfortunately, neither HDMI or standard DP to VGA is possible without an active digital to analog converter - it's not just a pin swap.

[strike]DisplayPort++ supports VGA output[/strike] (EDIT: Looks like DP++ is only DVI/HDMI), but the device needs to support it. Not all do.

What are you transmitting from?