Roger Long wrote:
I was just rummaging around in my computer elephant's graveyard and
realized that USB cables have four connectors, are black, and will fit
the Pfrank plug. I'll buy a 12 footer and cut the ends off.

I'd still like to hear if there is a cheaper way.

You really have to tell which GPS and what signals you want to carry.
For instance, an antennae wire is just a bit different from a power
cord. My older GPS needs power and passes basic NMEA at low speed.
For this, basic phone wire or cat 3/5 should be enough.